2405 lines
78 KiB
C
Executable File
2405 lines
78 KiB
C
Executable File
/*
|
|
** 2001 September 15
|
|
**
|
|
** The author disclaims copyright to this source code. In place of
|
|
** a legal notice, here is a blessing:
|
|
**
|
|
** May you do good and not evil.
|
|
** May you find forgiveness for yourself and forgive others.
|
|
** May you share freely, never taking more than you give.
|
|
**
|
|
*************************************************************************
|
|
** This file contains C code routines that are called by the parser
|
|
** to handle SELECT statements in SQLite.
|
|
**
|
|
** $Id: select.c,v 1.1.1.1 2004-03-11 22:22:23 alex Exp $
|
|
*/
|
|
#include "sqliteInt.h"
|
|
|
|
|
|
/*
|
|
** Allocate a new Select structure and return a pointer to that
|
|
** structure.
|
|
*/
|
|
Select *sqliteSelectNew(
|
|
ExprList *pEList, /* which columns to include in the result */
|
|
SrcList *pSrc, /* the FROM clause -- which tables to scan */
|
|
Expr *pWhere, /* the WHERE clause */
|
|
ExprList *pGroupBy, /* the GROUP BY clause */
|
|
Expr *pHaving, /* the HAVING clause */
|
|
ExprList *pOrderBy, /* the ORDER BY clause */
|
|
int isDistinct, /* true if the DISTINCT keyword is present */
|
|
int nLimit, /* LIMIT value. -1 means not used */
|
|
int nOffset /* OFFSET value. 0 means no offset */
|
|
){
|
|
Select *pNew;
|
|
pNew = sqliteMalloc( sizeof(*pNew) );
|
|
if( pNew==0 ){
|
|
sqliteExprListDelete(pEList);
|
|
sqliteSrcListDelete(pSrc);
|
|
sqliteExprDelete(pWhere);
|
|
sqliteExprListDelete(pGroupBy);
|
|
sqliteExprDelete(pHaving);
|
|
sqliteExprListDelete(pOrderBy);
|
|
}else{
|
|
if( pEList==0 ){
|
|
pEList = sqliteExprListAppend(0, sqliteExpr(TK_ALL,0,0,0), 0);
|
|
}
|
|
pNew->pEList = pEList;
|
|
pNew->pSrc = pSrc;
|
|
pNew->pWhere = pWhere;
|
|
pNew->pGroupBy = pGroupBy;
|
|
pNew->pHaving = pHaving;
|
|
pNew->pOrderBy = pOrderBy;
|
|
pNew->isDistinct = isDistinct;
|
|
pNew->op = TK_SELECT;
|
|
pNew->nLimit = nLimit;
|
|
pNew->nOffset = nOffset;
|
|
pNew->iLimit = -1;
|
|
pNew->iOffset = -1;
|
|
}
|
|
return pNew;
|
|
}
|
|
|
|
/*
|
|
** Given 1 to 3 identifiers preceeding the JOIN keyword, determine the
|
|
** type of join. Return an integer constant that expresses that type
|
|
** in terms of the following bit values:
|
|
**
|
|
** JT_INNER
|
|
** JT_OUTER
|
|
** JT_NATURAL
|
|
** JT_LEFT
|
|
** JT_RIGHT
|
|
**
|
|
** A full outer join is the combination of JT_LEFT and JT_RIGHT.
|
|
**
|
|
** If an illegal or unsupported join type is seen, then still return
|
|
** a join type, but put an error in the pParse structure.
|
|
*/
|
|
int sqliteJoinType(Parse *pParse, Token *pA, Token *pB, Token *pC){
|
|
int jointype = 0;
|
|
Token *apAll[3];
|
|
Token *p;
|
|
static struct {
|
|
const char *zKeyword;
|
|
int nChar;
|
|
int code;
|
|
} keywords[] = {
|
|
{ "natural", 7, JT_NATURAL },
|
|
{ "left", 4, JT_LEFT|JT_OUTER },
|
|
{ "right", 5, JT_RIGHT|JT_OUTER },
|
|
{ "full", 4, JT_LEFT|JT_RIGHT|JT_OUTER },
|
|
{ "outer", 5, JT_OUTER },
|
|
{ "inner", 5, JT_INNER },
|
|
{ "cross", 5, JT_INNER },
|
|
};
|
|
int i, j;
|
|
apAll[0] = pA;
|
|
apAll[1] = pB;
|
|
apAll[2] = pC;
|
|
for(i=0; i<3 && apAll[i]; i++){
|
|
p = apAll[i];
|
|
for(j=0; j<sizeof(keywords)/sizeof(keywords[0]); j++){
|
|
if( p->n==keywords[j].nChar
|
|
&& sqliteStrNICmp(p->z, keywords[j].zKeyword, p->n)==0 ){
|
|
jointype |= keywords[j].code;
|
|
break;
|
|
}
|
|
}
|
|
if( j>=sizeof(keywords)/sizeof(keywords[0]) ){
|
|
jointype |= JT_ERROR;
|
|
break;
|
|
}
|
|
}
|
|
if(
|
|
(jointype & (JT_INNER|JT_OUTER))==(JT_INNER|JT_OUTER) ||
|
|
(jointype & JT_ERROR)!=0
|
|
){
|
|
static Token dummy = { 0, 0 };
|
|
char *zSp1 = " ", *zSp2 = " ";
|
|
if( pB==0 ){ pB = &dummy; zSp1 = 0; }
|
|
if( pC==0 ){ pC = &dummy; zSp2 = 0; }
|
|
sqliteSetNString(&pParse->zErrMsg, "unknown or unsupported join type: ", 0,
|
|
pA->z, pA->n, zSp1, 1, pB->z, pB->n, zSp2, 1, pC->z, pC->n, 0);
|
|
pParse->nErr++;
|
|
jointype = JT_INNER;
|
|
}else if( jointype & JT_RIGHT ){
|
|
sqliteErrorMsg(pParse,
|
|
"RIGHT and FULL OUTER JOINs are not currently supported");
|
|
jointype = JT_INNER;
|
|
}
|
|
return jointype;
|
|
}
|
|
|
|
/*
|
|
** Return the index of a column in a table. Return -1 if the column
|
|
** is not contained in the table.
|
|
*/
|
|
static int columnIndex(Table *pTab, const char *zCol){
|
|
int i;
|
|
for(i=0; i<pTab->nCol; i++){
|
|
if( sqliteStrICmp(pTab->aCol[i].zName, zCol)==0 ) return i;
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
/*
|
|
** Add a term to the WHERE expression in *ppExpr that requires the
|
|
** zCol column to be equal in the two tables pTab1 and pTab2.
|
|
*/
|
|
static void addWhereTerm(
|
|
const char *zCol, /* Name of the column */
|
|
const Table *pTab1, /* First table */
|
|
const Table *pTab2, /* Second table */
|
|
Expr **ppExpr /* Add the equality term to this expression */
|
|
){
|
|
Token dummy;
|
|
Expr *pE1a, *pE1b, *pE1c;
|
|
Expr *pE2a, *pE2b, *pE2c;
|
|
Expr *pE;
|
|
|
|
dummy.z = zCol;
|
|
dummy.n = strlen(zCol);
|
|
dummy.dyn = 0;
|
|
pE1a = sqliteExpr(TK_ID, 0, 0, &dummy);
|
|
pE2a = sqliteExpr(TK_ID, 0, 0, &dummy);
|
|
dummy.z = pTab1->zName;
|
|
dummy.n = strlen(dummy.z);
|
|
pE1b = sqliteExpr(TK_ID, 0, 0, &dummy);
|
|
dummy.z = pTab2->zName;
|
|
dummy.n = strlen(dummy.z);
|
|
pE2b = sqliteExpr(TK_ID, 0, 0, &dummy);
|
|
pE1c = sqliteExpr(TK_DOT, pE1b, pE1a, 0);
|
|
pE2c = sqliteExpr(TK_DOT, pE2b, pE2a, 0);
|
|
pE = sqliteExpr(TK_EQ, pE1c, pE2c, 0);
|
|
ExprSetProperty(pE, EP_FromJoin);
|
|
if( *ppExpr ){
|
|
*ppExpr = sqliteExpr(TK_AND, *ppExpr, pE, 0);
|
|
}else{
|
|
*ppExpr = pE;
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Set the EP_FromJoin property on all terms of the given expression.
|
|
**
|
|
** The EP_FromJoin property is used on terms of an expression to tell
|
|
** the LEFT OUTER JOIN processing logic that this term is part of the
|
|
** join restriction specified in the ON or USING clause and not a part
|
|
** of the more general WHERE clause. These terms are moved over to the
|
|
** WHERE clause during join processing but we need to remember that they
|
|
** originated in the ON or USING clause.
|
|
*/
|
|
static void setJoinExpr(Expr *p){
|
|
while( p ){
|
|
ExprSetProperty(p, EP_FromJoin);
|
|
setJoinExpr(p->pLeft);
|
|
p = p->pRight;
|
|
}
|
|
}
|
|
|
|
/*
|
|
** This routine processes the join information for a SELECT statement.
|
|
** ON and USING clauses are converted into extra terms of the WHERE clause.
|
|
** NATURAL joins also create extra WHERE clause terms.
|
|
**
|
|
** This routine returns the number of errors encountered.
|
|
*/
|
|
static int sqliteProcessJoin(Parse *pParse, Select *p){
|
|
SrcList *pSrc;
|
|
int i, j;
|
|
pSrc = p->pSrc;
|
|
for(i=0; i<pSrc->nSrc-1; i++){
|
|
struct SrcList_item *pTerm = &pSrc->a[i];
|
|
struct SrcList_item *pOther = &pSrc->a[i+1];
|
|
|
|
if( pTerm->pTab==0 || pOther->pTab==0 ) continue;
|
|
|
|
/* When the NATURAL keyword is present, add WHERE clause terms for
|
|
** every column that the two tables have in common.
|
|
*/
|
|
if( pTerm->jointype & JT_NATURAL ){
|
|
Table *pTab;
|
|
if( pTerm->pOn || pTerm->pUsing ){
|
|
sqliteErrorMsg(pParse, "a NATURAL join may not have "
|
|
"an ON or USING clause", 0);
|
|
return 1;
|
|
}
|
|
pTab = pTerm->pTab;
|
|
for(j=0; j<pTab->nCol; j++){
|
|
if( columnIndex(pOther->pTab, pTab->aCol[j].zName)>=0 ){
|
|
addWhereTerm(pTab->aCol[j].zName, pTab, pOther->pTab, &p->pWhere);
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Disallow both ON and USING clauses in the same join
|
|
*/
|
|
if( pTerm->pOn && pTerm->pUsing ){
|
|
sqliteErrorMsg(pParse, "cannot have both ON and USING "
|
|
"clauses in the same join");
|
|
return 1;
|
|
}
|
|
|
|
/* Add the ON clause to the end of the WHERE clause, connected by
|
|
** and AND operator.
|
|
*/
|
|
if( pTerm->pOn ){
|
|
setJoinExpr(pTerm->pOn);
|
|
if( p->pWhere==0 ){
|
|
p->pWhere = pTerm->pOn;
|
|
}else{
|
|
p->pWhere = sqliteExpr(TK_AND, p->pWhere, pTerm->pOn, 0);
|
|
}
|
|
pTerm->pOn = 0;
|
|
}
|
|
|
|
/* Create extra terms on the WHERE clause for each column named
|
|
** in the USING clause. Example: If the two tables to be joined are
|
|
** A and B and the USING clause names X, Y, and Z, then add this
|
|
** to the WHERE clause: A.X=B.X AND A.Y=B.Y AND A.Z=B.Z
|
|
** Report an error if any column mentioned in the USING clause is
|
|
** not contained in both tables to be joined.
|
|
*/
|
|
if( pTerm->pUsing ){
|
|
IdList *pList;
|
|
int j;
|
|
assert( i<pSrc->nSrc-1 );
|
|
pList = pTerm->pUsing;
|
|
for(j=0; j<pList->nId; j++){
|
|
if( columnIndex(pTerm->pTab, pList->a[j].zName)<0 ||
|
|
columnIndex(pOther->pTab, pList->a[j].zName)<0 ){
|
|
sqliteErrorMsg(pParse, "cannot join using column %s - column "
|
|
"not present in both tables", pList->a[j].zName);
|
|
return 1;
|
|
}
|
|
addWhereTerm(pList->a[j].zName, pTerm->pTab, pOther->pTab, &p->pWhere);
|
|
}
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
** Delete the given Select structure and all of its substructures.
|
|
*/
|
|
void sqliteSelectDelete(Select *p){
|
|
if( p==0 ) return;
|
|
sqliteExprListDelete(p->pEList);
|
|
sqliteSrcListDelete(p->pSrc);
|
|
sqliteExprDelete(p->pWhere);
|
|
sqliteExprListDelete(p->pGroupBy);
|
|
sqliteExprDelete(p->pHaving);
|
|
sqliteExprListDelete(p->pOrderBy);
|
|
sqliteSelectDelete(p->pPrior);
|
|
sqliteFree(p->zSelect);
|
|
sqliteFree(p);
|
|
}
|
|
|
|
/*
|
|
** Delete the aggregate information from the parse structure.
|
|
*/
|
|
static void sqliteAggregateInfoReset(Parse *pParse){
|
|
sqliteFree(pParse->aAgg);
|
|
pParse->aAgg = 0;
|
|
pParse->nAgg = 0;
|
|
pParse->useAgg = 0;
|
|
}
|
|
|
|
/*
|
|
** Insert code into "v" that will push the record on the top of the
|
|
** stack into the sorter.
|
|
*/
|
|
static void pushOntoSorter(Parse *pParse, Vdbe *v, ExprList *pOrderBy){
|
|
char *zSortOrder;
|
|
int i;
|
|
zSortOrder = sqliteMalloc( pOrderBy->nExpr + 1 );
|
|
if( zSortOrder==0 ) return;
|
|
for(i=0; i<pOrderBy->nExpr; i++){
|
|
int order = pOrderBy->a[i].sortOrder;
|
|
int type;
|
|
int c;
|
|
if( (order & SQLITE_SO_TYPEMASK)==SQLITE_SO_TEXT ){
|
|
type = SQLITE_SO_TEXT;
|
|
}else if( (order & SQLITE_SO_TYPEMASK)==SQLITE_SO_NUM ){
|
|
type = SQLITE_SO_NUM;
|
|
}else if( pParse->db->file_format>=4 ){
|
|
type = sqliteExprType(pOrderBy->a[i].pExpr);
|
|
}else{
|
|
type = SQLITE_SO_NUM;
|
|
}
|
|
if( (order & SQLITE_SO_DIRMASK)==SQLITE_SO_ASC ){
|
|
c = type==SQLITE_SO_TEXT ? 'A' : '+';
|
|
}else{
|
|
c = type==SQLITE_SO_TEXT ? 'D' : '-';
|
|
}
|
|
zSortOrder[i] = c;
|
|
sqliteExprCode(pParse, pOrderBy->a[i].pExpr);
|
|
}
|
|
zSortOrder[pOrderBy->nExpr] = 0;
|
|
sqliteVdbeOp3(v, OP_SortMakeKey, pOrderBy->nExpr, 0, zSortOrder, P3_DYNAMIC);
|
|
sqliteVdbeAddOp(v, OP_SortPut, 0, 0);
|
|
}
|
|
|
|
/*
|
|
** This routine adds a P3 argument to the last VDBE opcode that was
|
|
** inserted. The P3 argument added is a string suitable for the
|
|
** OP_MakeKey or OP_MakeIdxKey opcodes. The string consists of
|
|
** characters 't' or 'n' depending on whether or not the various
|
|
** fields of the key to be generated should be treated as numeric
|
|
** or as text. See the OP_MakeKey and OP_MakeIdxKey opcode
|
|
** documentation for additional information about the P3 string.
|
|
** See also the sqliteAddIdxKeyType() routine.
|
|
*/
|
|
void sqliteAddKeyType(Vdbe *v, ExprList *pEList){
|
|
int nColumn = pEList->nExpr;
|
|
char *zType = sqliteMalloc( nColumn+1 );
|
|
int i;
|
|
if( zType==0 ) return;
|
|
for(i=0; i<nColumn; i++){
|
|
zType[i] = sqliteExprType(pEList->a[i].pExpr)==SQLITE_SO_NUM ? 'n' : 't';
|
|
}
|
|
zType[i] = 0;
|
|
sqliteVdbeChangeP3(v, -1, zType, P3_DYNAMIC);
|
|
}
|
|
|
|
/*
|
|
** This routine generates the code for the inside of the inner loop
|
|
** of a SELECT.
|
|
**
|
|
** If srcTab and nColumn are both zero, then the pEList expressions
|
|
** are evaluated in order to get the data for this row. If nColumn>0
|
|
** then data is pulled from srcTab and pEList is used only to get the
|
|
** datatypes for each column.
|
|
*/
|
|
static int selectInnerLoop(
|
|
Parse *pParse, /* The parser context */
|
|
Select *p, /* The complete select statement being coded */
|
|
ExprList *pEList, /* List of values being extracted */
|
|
int srcTab, /* Pull data from this table */
|
|
int nColumn, /* Number of columns in the source table */
|
|
ExprList *pOrderBy, /* If not NULL, sort results using this key */
|
|
int distinct, /* If >=0, make sure results are distinct */
|
|
int eDest, /* How to dispose of the results */
|
|
int iParm, /* An argument to the disposal method */
|
|
int iContinue, /* Jump here to continue with next row */
|
|
int iBreak /* Jump here to break out of the inner loop */
|
|
){
|
|
Vdbe *v = pParse->pVdbe;
|
|
int i;
|
|
|
|
if( v==0 ) return 0;
|
|
assert( pEList!=0 );
|
|
|
|
/* If there was a LIMIT clause on the SELECT statement, then do the check
|
|
** to see if this row should be output.
|
|
*/
|
|
if( pOrderBy==0 ){
|
|
if( p->iOffset>=0 ){
|
|
int addr = sqliteVdbeCurrentAddr(v);
|
|
sqliteVdbeAddOp(v, OP_MemIncr, p->iOffset, addr+2);
|
|
sqliteVdbeAddOp(v, OP_Goto, 0, iContinue);
|
|
}
|
|
if( p->iLimit>=0 ){
|
|
sqliteVdbeAddOp(v, OP_MemIncr, p->iLimit, iBreak);
|
|
}
|
|
}
|
|
|
|
/* Pull the requested columns.
|
|
*/
|
|
if( nColumn>0 ){
|
|
for(i=0; i<nColumn; i++){
|
|
sqliteVdbeAddOp(v, OP_Column, srcTab, i);
|
|
}
|
|
}else{
|
|
nColumn = pEList->nExpr;
|
|
for(i=0; i<pEList->nExpr; i++){
|
|
sqliteExprCode(pParse, pEList->a[i].pExpr);
|
|
}
|
|
}
|
|
|
|
/* If the DISTINCT keyword was present on the SELECT statement
|
|
** and this row has been seen before, then do not make this row
|
|
** part of the result.
|
|
*/
|
|
if( distinct>=0 && pEList && pEList->nExpr>0 ){
|
|
#if NULL_ALWAYS_DISTINCT
|
|
sqliteVdbeAddOp(v, OP_IsNull, -pEList->nExpr, sqliteVdbeCurrentAddr(v)+7);
|
|
#endif
|
|
sqliteVdbeAddOp(v, OP_MakeKey, pEList->nExpr, 1);
|
|
if( pParse->db->file_format>=4 ) sqliteAddKeyType(v, pEList);
|
|
sqliteVdbeAddOp(v, OP_Distinct, distinct, sqliteVdbeCurrentAddr(v)+3);
|
|
sqliteVdbeAddOp(v, OP_Pop, pEList->nExpr+1, 0);
|
|
sqliteVdbeAddOp(v, OP_Goto, 0, iContinue);
|
|
sqliteVdbeAddOp(v, OP_String, 0, 0);
|
|
sqliteVdbeAddOp(v, OP_PutStrKey, distinct, 0);
|
|
}
|
|
|
|
switch( eDest ){
|
|
/* In this mode, write each query result to the key of the temporary
|
|
** table iParm.
|
|
*/
|
|
case SRT_Union: {
|
|
sqliteVdbeAddOp(v, OP_MakeRecord, nColumn, NULL_ALWAYS_DISTINCT);
|
|
sqliteVdbeAddOp(v, OP_String, 0, 0);
|
|
sqliteVdbeAddOp(v, OP_PutStrKey, iParm, 0);
|
|
break;
|
|
}
|
|
|
|
/* Store the result as data using a unique key.
|
|
*/
|
|
case SRT_Table:
|
|
case SRT_TempTable: {
|
|
sqliteVdbeAddOp(v, OP_MakeRecord, nColumn, 0);
|
|
if( pOrderBy ){
|
|
pushOntoSorter(pParse, v, pOrderBy);
|
|
}else{
|
|
sqliteVdbeAddOp(v, OP_NewRecno, iParm, 0);
|
|
sqliteVdbeAddOp(v, OP_Pull, 1, 0);
|
|
sqliteVdbeAddOp(v, OP_PutIntKey, iParm, 0);
|
|
}
|
|
break;
|
|
}
|
|
|
|
/* Construct a record from the query result, but instead of
|
|
** saving that record, use it as a key to delete elements from
|
|
** the temporary table iParm.
|
|
*/
|
|
case SRT_Except: {
|
|
int addr;
|
|
addr = sqliteVdbeAddOp(v, OP_MakeRecord, nColumn, NULL_ALWAYS_DISTINCT);
|
|
sqliteVdbeAddOp(v, OP_NotFound, iParm, addr+3);
|
|
sqliteVdbeAddOp(v, OP_Delete, iParm, 0);
|
|
break;
|
|
}
|
|
|
|
/* If we are creating a set for an "expr IN (SELECT ...)" construct,
|
|
** then there should be a single item on the stack. Write this
|
|
** item into the set table with bogus data.
|
|
*/
|
|
case SRT_Set: {
|
|
int addr1 = sqliteVdbeCurrentAddr(v);
|
|
int addr2;
|
|
assert( nColumn==1 );
|
|
sqliteVdbeAddOp(v, OP_NotNull, -1, addr1+3);
|
|
sqliteVdbeAddOp(v, OP_Pop, 1, 0);
|
|
addr2 = sqliteVdbeAddOp(v, OP_Goto, 0, 0);
|
|
if( pOrderBy ){
|
|
pushOntoSorter(pParse, v, pOrderBy);
|
|
}else{
|
|
sqliteVdbeAddOp(v, OP_String, 0, 0);
|
|
sqliteVdbeAddOp(v, OP_PutStrKey, iParm, 0);
|
|
}
|
|
sqliteVdbeChangeP2(v, addr2, sqliteVdbeCurrentAddr(v));
|
|
break;
|
|
}
|
|
|
|
/* If this is a scalar select that is part of an expression, then
|
|
** store the results in the appropriate memory cell and break out
|
|
** of the scan loop.
|
|
*/
|
|
case SRT_Mem: {
|
|
assert( nColumn==1 );
|
|
if( pOrderBy ){
|
|
pushOntoSorter(pParse, v, pOrderBy);
|
|
}else{
|
|
sqliteVdbeAddOp(v, OP_MemStore, iParm, 1);
|
|
sqliteVdbeAddOp(v, OP_Goto, 0, iBreak);
|
|
}
|
|
break;
|
|
}
|
|
|
|
/* Send the data to the callback function.
|
|
*/
|
|
case SRT_Callback:
|
|
case SRT_Sorter: {
|
|
if( pOrderBy ){
|
|
sqliteVdbeAddOp(v, OP_SortMakeRec, nColumn, 0);
|
|
pushOntoSorter(pParse, v, pOrderBy);
|
|
}else{
|
|
assert( eDest==SRT_Callback );
|
|
sqliteVdbeAddOp(v, OP_Callback, nColumn, 0);
|
|
}
|
|
break;
|
|
}
|
|
|
|
/* Invoke a subroutine to handle the results. The subroutine itself
|
|
** is responsible for popping the results off of the stack.
|
|
*/
|
|
case SRT_Subroutine: {
|
|
if( pOrderBy ){
|
|
sqliteVdbeAddOp(v, OP_MakeRecord, nColumn, 0);
|
|
pushOntoSorter(pParse, v, pOrderBy);
|
|
}else{
|
|
sqliteVdbeAddOp(v, OP_Gosub, 0, iParm);
|
|
}
|
|
break;
|
|
}
|
|
|
|
/* Discard the results. This is used for SELECT statements inside
|
|
** the body of a TRIGGER. The purpose of such selects is to call
|
|
** user-defined functions that have side effects. We do not care
|
|
** about the actual results of the select.
|
|
*/
|
|
default: {
|
|
assert( eDest==SRT_Discard );
|
|
sqliteVdbeAddOp(v, OP_Pop, nColumn, 0);
|
|
break;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
** If the inner loop was generated using a non-null pOrderBy argument,
|
|
** then the results were placed in a sorter. After the loop is terminated
|
|
** we need to run the sorter and output the results. The following
|
|
** routine generates the code needed to do that.
|
|
*/
|
|
static void generateSortTail(
|
|
Select *p, /* The SELECT statement */
|
|
Vdbe *v, /* Generate code into this VDBE */
|
|
int nColumn, /* Number of columns of data */
|
|
int eDest, /* Write the sorted results here */
|
|
int iParm /* Optional parameter associated with eDest */
|
|
){
|
|
int end1 = sqliteVdbeMakeLabel(v);
|
|
int end2 = sqliteVdbeMakeLabel(v);
|
|
int addr;
|
|
if( eDest==SRT_Sorter ) return;
|
|
sqliteVdbeAddOp(v, OP_Sort, 0, 0);
|
|
addr = sqliteVdbeAddOp(v, OP_SortNext, 0, end1);
|
|
if( p->iOffset>=0 ){
|
|
sqliteVdbeAddOp(v, OP_MemIncr, p->iOffset, addr+4);
|
|
sqliteVdbeAddOp(v, OP_Pop, 1, 0);
|
|
sqliteVdbeAddOp(v, OP_Goto, 0, addr);
|
|
}
|
|
if( p->iLimit>=0 ){
|
|
sqliteVdbeAddOp(v, OP_MemIncr, p->iLimit, end2);
|
|
}
|
|
switch( eDest ){
|
|
case SRT_Callback: {
|
|
sqliteVdbeAddOp(v, OP_SortCallback, nColumn, 0);
|
|
break;
|
|
}
|
|
case SRT_Table:
|
|
case SRT_TempTable: {
|
|
sqliteVdbeAddOp(v, OP_NewRecno, iParm, 0);
|
|
sqliteVdbeAddOp(v, OP_Pull, 1, 0);
|
|
sqliteVdbeAddOp(v, OP_PutIntKey, iParm, 0);
|
|
break;
|
|
}
|
|
case SRT_Set: {
|
|
assert( nColumn==1 );
|
|
sqliteVdbeAddOp(v, OP_NotNull, -1, sqliteVdbeCurrentAddr(v)+3);
|
|
sqliteVdbeAddOp(v, OP_Pop, 1, 0);
|
|
sqliteVdbeAddOp(v, OP_Goto, 0, sqliteVdbeCurrentAddr(v)+3);
|
|
sqliteVdbeAddOp(v, OP_String, 0, 0);
|
|
sqliteVdbeAddOp(v, OP_PutStrKey, iParm, 0);
|
|
break;
|
|
}
|
|
case SRT_Mem: {
|
|
assert( nColumn==1 );
|
|
sqliteVdbeAddOp(v, OP_MemStore, iParm, 1);
|
|
sqliteVdbeAddOp(v, OP_Goto, 0, end1);
|
|
break;
|
|
}
|
|
case SRT_Subroutine: {
|
|
int i;
|
|
for(i=0; i<nColumn; i++){
|
|
sqliteVdbeAddOp(v, OP_Column, -1-i, i);
|
|
}
|
|
sqliteVdbeAddOp(v, OP_Gosub, 0, iParm);
|
|
sqliteVdbeAddOp(v, OP_Pop, 1, 0);
|
|
break;
|
|
}
|
|
default: {
|
|
/* Do nothing */
|
|
break;
|
|
}
|
|
}
|
|
sqliteVdbeAddOp(v, OP_Goto, 0, addr);
|
|
sqliteVdbeResolveLabel(v, end2);
|
|
sqliteVdbeAddOp(v, OP_Pop, 1, 0);
|
|
sqliteVdbeResolveLabel(v, end1);
|
|
sqliteVdbeAddOp(v, OP_SortReset, 0, 0);
|
|
}
|
|
|
|
/*
|
|
** Generate code that will tell the VDBE the datatypes of
|
|
** columns in the result set.
|
|
**
|
|
** This routine only generates code if the "PRAGMA show_datatypes=on"
|
|
** has been executed. The datatypes are reported out in the azCol
|
|
** parameter to the callback function. The first N azCol[] entries
|
|
** are the names of the columns, and the second N entries are the
|
|
** datatypes for the columns.
|
|
**
|
|
** The "datatype" for a result that is a column of a type is the
|
|
** datatype definition extracted from the CREATE TABLE statement.
|
|
** The datatype for an expression is either TEXT or NUMERIC. The
|
|
** datatype for a ROWID field is INTEGER.
|
|
*/
|
|
static void generateColumnTypes(
|
|
Parse *pParse, /* Parser context */
|
|
SrcList *pTabList, /* List of tables */
|
|
ExprList *pEList /* Expressions defining the result set */
|
|
){
|
|
Vdbe *v = pParse->pVdbe;
|
|
int i, j;
|
|
for(i=0; i<pEList->nExpr; i++){
|
|
Expr *p = pEList->a[i].pExpr;
|
|
char *zType = 0;
|
|
if( p==0 ) continue;
|
|
if( p->op==TK_COLUMN && pTabList ){
|
|
Table *pTab;
|
|
int iCol = p->iColumn;
|
|
for(j=0; j<pTabList->nSrc && pTabList->a[j].iCursor!=p->iTable; j++){}
|
|
assert( j<pTabList->nSrc );
|
|
pTab = pTabList->a[j].pTab;
|
|
if( iCol<0 ) iCol = pTab->iPKey;
|
|
assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
|
|
if( iCol<0 ){
|
|
zType = "INTEGER";
|
|
}else{
|
|
zType = pTab->aCol[iCol].zType;
|
|
}
|
|
}else{
|
|
if( sqliteExprType(p)==SQLITE_SO_TEXT ){
|
|
zType = "TEXT";
|
|
}else{
|
|
zType = "NUMERIC";
|
|
}
|
|
}
|
|
sqliteVdbeOp3(v, OP_ColumnName, i + pEList->nExpr, 0, zType, 0);
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Generate code that will tell the VDBE the names of columns
|
|
** in the result set. This information is used to provide the
|
|
** azCol[] values in the callback.
|
|
*/
|
|
static void generateColumnNames(
|
|
Parse *pParse, /* Parser context */
|
|
SrcList *pTabList, /* List of tables */
|
|
ExprList *pEList /* Expressions defining the result set */
|
|
){
|
|
Vdbe *v = pParse->pVdbe;
|
|
int i, j;
|
|
sqlite *db = pParse->db;
|
|
int fullNames, shortNames;
|
|
|
|
assert( v!=0 );
|
|
if( pParse->colNamesSet || v==0 || sqlite_malloc_failed ) return;
|
|
pParse->colNamesSet = 1;
|
|
fullNames = (db->flags & SQLITE_FullColNames)!=0;
|
|
shortNames = (db->flags & SQLITE_ShortColNames)!=0;
|
|
for(i=0; i<pEList->nExpr; i++){
|
|
Expr *p;
|
|
int p2 = i==pEList->nExpr-1;
|
|
p = pEList->a[i].pExpr;
|
|
if( p==0 ) continue;
|
|
if( pEList->a[i].zName ){
|
|
char *zName = pEList->a[i].zName;
|
|
sqliteVdbeOp3(v, OP_ColumnName, i, p2, zName, 0);
|
|
continue;
|
|
}
|
|
if( p->op==TK_COLUMN && pTabList ){
|
|
Table *pTab;
|
|
char *zCol;
|
|
int iCol = p->iColumn;
|
|
for(j=0; j<pTabList->nSrc && pTabList->a[j].iCursor!=p->iTable; j++){}
|
|
assert( j<pTabList->nSrc );
|
|
pTab = pTabList->a[j].pTab;
|
|
if( iCol<0 ) iCol = pTab->iPKey;
|
|
assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
|
|
if( iCol<0 ){
|
|
zCol = "_ROWID_";
|
|
}else{
|
|
zCol = pTab->aCol[iCol].zName;
|
|
}
|
|
if( !shortNames && !fullNames && p->span.z && p->span.z[0] ){
|
|
int addr = sqliteVdbeOp3(v,OP_ColumnName, i, p2, p->span.z, p->span.n);
|
|
sqliteVdbeCompressSpace(v, addr);
|
|
}else if( fullNames || (!shortNames && pTabList->nSrc>1) ){
|
|
char *zName = 0;
|
|
char *zTab;
|
|
|
|
zTab = pTabList->a[j].zAlias;
|
|
if( fullNames || zTab==0 ) zTab = pTab->zName;
|
|
sqliteSetString(&zName, zTab, ".", zCol, 0);
|
|
sqliteVdbeOp3(v, OP_ColumnName, i, p2, zName, P3_DYNAMIC);
|
|
}else{
|
|
sqliteVdbeOp3(v, OP_ColumnName, i, p2, zCol, 0);
|
|
}
|
|
}else if( p->span.z && p->span.z[0] ){
|
|
int addr = sqliteVdbeOp3(v,OP_ColumnName, i, p2, p->span.z, p->span.n);
|
|
sqliteVdbeCompressSpace(v, addr);
|
|
}else{
|
|
char zName[30];
|
|
assert( p->op!=TK_COLUMN || pTabList==0 );
|
|
sprintf(zName, "column%d", i+1);
|
|
sqliteVdbeOp3(v, OP_ColumnName, i, p2, zName, 0);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Name of the connection operator, used for error messages.
|
|
*/
|
|
static const char *selectOpName(int id){
|
|
char *z;
|
|
switch( id ){
|
|
case TK_ALL: z = "UNION ALL"; break;
|
|
case TK_INTERSECT: z = "INTERSECT"; break;
|
|
case TK_EXCEPT: z = "EXCEPT"; break;
|
|
default: z = "UNION"; break;
|
|
}
|
|
return z;
|
|
}
|
|
|
|
/*
|
|
** Forward declaration
|
|
*/
|
|
static int fillInColumnList(Parse*, Select*);
|
|
|
|
/*
|
|
** Given a SELECT statement, generate a Table structure that describes
|
|
** the result set of that SELECT.
|
|
*/
|
|
Table *sqliteResultSetOfSelect(Parse *pParse, char *zTabName, Select *pSelect){
|
|
Table *pTab;
|
|
int i, j;
|
|
ExprList *pEList;
|
|
Column *aCol;
|
|
|
|
if( fillInColumnList(pParse, pSelect) ){
|
|
return 0;
|
|
}
|
|
pTab = sqliteMalloc( sizeof(Table) );
|
|
if( pTab==0 ){
|
|
return 0;
|
|
}
|
|
pTab->zName = zTabName ? sqliteStrDup(zTabName) : 0;
|
|
pEList = pSelect->pEList;
|
|
pTab->nCol = pEList->nExpr;
|
|
assert( pTab->nCol>0 );
|
|
pTab->aCol = aCol = sqliteMalloc( sizeof(pTab->aCol[0])*pTab->nCol );
|
|
for(i=0; i<pTab->nCol; i++){
|
|
Expr *p, *pR;
|
|
if( pEList->a[i].zName ){
|
|
aCol[i].zName = sqliteStrDup(pEList->a[i].zName);
|
|
}else if( (p=pEList->a[i].pExpr)->op==TK_DOT
|
|
&& (pR=p->pRight)!=0 && pR->token.z && pR->token.z[0] ){
|
|
int cnt;
|
|
sqliteSetNString(&aCol[i].zName, pR->token.z, pR->token.n, 0);
|
|
for(j=cnt=0; j<i; j++){
|
|
if( sqliteStrICmp(aCol[j].zName, aCol[i].zName)==0 ){
|
|
int n;
|
|
char zBuf[30];
|
|
sprintf(zBuf,"_%d",++cnt);
|
|
n = strlen(zBuf);
|
|
sqliteSetNString(&aCol[i].zName, pR->token.z, pR->token.n, zBuf, n,0);
|
|
j = -1;
|
|
}
|
|
}
|
|
}else if( p->span.z && p->span.z[0] ){
|
|
sqliteSetNString(&pTab->aCol[i].zName, p->span.z, p->span.n, 0);
|
|
}else{
|
|
char zBuf[30];
|
|
sprintf(zBuf, "column%d", i+1);
|
|
pTab->aCol[i].zName = sqliteStrDup(zBuf);
|
|
}
|
|
}
|
|
pTab->iPKey = -1;
|
|
return pTab;
|
|
}
|
|
|
|
/*
|
|
** For the given SELECT statement, do three things.
|
|
**
|
|
** (1) Fill in the pTabList->a[].pTab fields in the SrcList that
|
|
** defines the set of tables that should be scanned. For views,
|
|
** fill pTabList->a[].pSelect with a copy of the SELECT statement
|
|
** that implements the view. A copy is made of the view's SELECT
|
|
** statement so that we can freely modify or delete that statement
|
|
** without worrying about messing up the presistent representation
|
|
** of the view.
|
|
**
|
|
** (2) Add terms to the WHERE clause to accomodate the NATURAL keyword
|
|
** on joins and the ON and USING clause of joins.
|
|
**
|
|
** (3) Scan the list of columns in the result set (pEList) looking
|
|
** for instances of the "*" operator or the TABLE.* operator.
|
|
** If found, expand each "*" to be every column in every table
|
|
** and TABLE.* to be every column in TABLE.
|
|
**
|
|
** Return 0 on success. If there are problems, leave an error message
|
|
** in pParse and return non-zero.
|
|
*/
|
|
static int fillInColumnList(Parse *pParse, Select *p){
|
|
int i, j, k, rc;
|
|
SrcList *pTabList;
|
|
ExprList *pEList;
|
|
Table *pTab;
|
|
|
|
if( p==0 || p->pSrc==0 ) return 1;
|
|
pTabList = p->pSrc;
|
|
pEList = p->pEList;
|
|
|
|
/* Look up every table in the table list.
|
|
*/
|
|
for(i=0; i<pTabList->nSrc; i++){
|
|
if( pTabList->a[i].pTab ){
|
|
/* This routine has run before! No need to continue */
|
|
return 0;
|
|
}
|
|
if( pTabList->a[i].zName==0 ){
|
|
/* A sub-query in the FROM clause of a SELECT */
|
|
assert( pTabList->a[i].pSelect!=0 );
|
|
if( pTabList->a[i].zAlias==0 ){
|
|
char zFakeName[60];
|
|
sprintf(zFakeName, "sqlite_subquery_%p_",
|
|
(void*)pTabList->a[i].pSelect);
|
|
sqliteSetString(&pTabList->a[i].zAlias, zFakeName, 0);
|
|
}
|
|
pTabList->a[i].pTab = pTab =
|
|
sqliteResultSetOfSelect(pParse, pTabList->a[i].zAlias,
|
|
pTabList->a[i].pSelect);
|
|
if( pTab==0 ){
|
|
return 1;
|
|
}
|
|
/* The isTransient flag indicates that the Table structure has been
|
|
** dynamically allocated and may be freed at any time. In other words,
|
|
** pTab is not pointing to a persistent table structure that defines
|
|
** part of the schema. */
|
|
pTab->isTransient = 1;
|
|
}else{
|
|
/* An ordinary table or view name in the FROM clause */
|
|
pTabList->a[i].pTab = pTab =
|
|
sqliteLocateTable(pParse,pTabList->a[i].zName,pTabList->a[i].zDatabase);
|
|
if( pTab==0 ){
|
|
return 1;
|
|
}
|
|
if( pTab->pSelect ){
|
|
/* We reach here if the named table is a really a view */
|
|
if( sqliteViewGetColumnNames(pParse, pTab) ){
|
|
return 1;
|
|
}
|
|
/* If pTabList->a[i].pSelect!=0 it means we are dealing with a
|
|
** view within a view. The SELECT structure has already been
|
|
** copied by the outer view so we can skip the copy step here
|
|
** in the inner view.
|
|
*/
|
|
if( pTabList->a[i].pSelect==0 ){
|
|
pTabList->a[i].pSelect = sqliteSelectDup(pTab->pSelect);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Process NATURAL keywords, and ON and USING clauses of joins.
|
|
*/
|
|
if( sqliteProcessJoin(pParse, p) ) return 1;
|
|
|
|
/* For every "*" that occurs in the column list, insert the names of
|
|
** all columns in all tables. And for every TABLE.* insert the names
|
|
** of all columns in TABLE. The parser inserted a special expression
|
|
** with the TK_ALL operator for each "*" that it found in the column list.
|
|
** The following code just has to locate the TK_ALL expressions and expand
|
|
** each one to the list of all columns in all tables.
|
|
**
|
|
** The first loop just checks to see if there are any "*" operators
|
|
** that need expanding.
|
|
*/
|
|
for(k=0; k<pEList->nExpr; k++){
|
|
Expr *pE = pEList->a[k].pExpr;
|
|
if( pE->op==TK_ALL ) break;
|
|
if( pE->op==TK_DOT && pE->pRight && pE->pRight->op==TK_ALL
|
|
&& pE->pLeft && pE->pLeft->op==TK_ID ) break;
|
|
}
|
|
rc = 0;
|
|
if( k<pEList->nExpr ){
|
|
/*
|
|
** If we get here it means the result set contains one or more "*"
|
|
** operators that need to be expanded. Loop through each expression
|
|
** in the result set and expand them one by one.
|
|
*/
|
|
struct ExprList_item *a = pEList->a;
|
|
ExprList *pNew = 0;
|
|
for(k=0; k<pEList->nExpr; k++){
|
|
Expr *pE = a[k].pExpr;
|
|
if( pE->op!=TK_ALL &&
|
|
(pE->op!=TK_DOT || pE->pRight==0 || pE->pRight->op!=TK_ALL) ){
|
|
/* This particular expression does not need to be expanded.
|
|
*/
|
|
pNew = sqliteExprListAppend(pNew, a[k].pExpr, 0);
|
|
pNew->a[pNew->nExpr-1].zName = a[k].zName;
|
|
a[k].pExpr = 0;
|
|
a[k].zName = 0;
|
|
}else{
|
|
/* This expression is a "*" or a "TABLE.*" and needs to be
|
|
** expanded. */
|
|
int tableSeen = 0; /* Set to 1 when TABLE matches */
|
|
Token *pName; /* text of name of TABLE */
|
|
if( pE->op==TK_DOT && pE->pLeft ){
|
|
pName = &pE->pLeft->token;
|
|
}else{
|
|
pName = 0;
|
|
}
|
|
for(i=0; i<pTabList->nSrc; i++){
|
|
Table *pTab = pTabList->a[i].pTab;
|
|
char *zTabName = pTabList->a[i].zAlias;
|
|
if( zTabName==0 || zTabName[0]==0 ){
|
|
zTabName = pTab->zName;
|
|
}
|
|
if( pName && (zTabName==0 || zTabName[0]==0 ||
|
|
sqliteStrNICmp(pName->z, zTabName, pName->n)!=0 ||
|
|
zTabName[pName->n]!=0) ){
|
|
continue;
|
|
}
|
|
tableSeen = 1;
|
|
for(j=0; j<pTab->nCol; j++){
|
|
Expr *pExpr, *pLeft, *pRight;
|
|
char *zName = pTab->aCol[j].zName;
|
|
|
|
if( i>0 && (pTabList->a[i-1].jointype & JT_NATURAL)!=0 &&
|
|
columnIndex(pTabList->a[i-1].pTab, zName)>=0 ){
|
|
/* In a NATURAL join, omit the join columns from the
|
|
** table on the right */
|
|
continue;
|
|
}
|
|
if( i>0 && sqliteIdListIndex(pTabList->a[i-1].pUsing, zName)>=0 ){
|
|
/* In a join with a USING clause, omit columns in the
|
|
** using clause from the table on the right. */
|
|
continue;
|
|
}
|
|
pRight = sqliteExpr(TK_ID, 0, 0, 0);
|
|
if( pRight==0 ) break;
|
|
pRight->token.z = zName;
|
|
pRight->token.n = strlen(zName);
|
|
pRight->token.dyn = 0;
|
|
if( zTabName && pTabList->nSrc>1 ){
|
|
pLeft = sqliteExpr(TK_ID, 0, 0, 0);
|
|
pExpr = sqliteExpr(TK_DOT, pLeft, pRight, 0);
|
|
if( pExpr==0 ) break;
|
|
pLeft->token.z = zTabName;
|
|
pLeft->token.n = strlen(zTabName);
|
|
pLeft->token.dyn = 0;
|
|
sqliteSetString((char**)&pExpr->span.z, zTabName, ".", zName, 0);
|
|
pExpr->span.n = strlen(pExpr->span.z);
|
|
pExpr->span.dyn = 1;
|
|
pExpr->token.z = 0;
|
|
pExpr->token.n = 0;
|
|
pExpr->token.dyn = 0;
|
|
}else{
|
|
pExpr = pRight;
|
|
pExpr->span = pExpr->token;
|
|
}
|
|
pNew = sqliteExprListAppend(pNew, pExpr, 0);
|
|
}
|
|
}
|
|
if( !tableSeen ){
|
|
if( pName ){
|
|
sqliteErrorMsg(pParse, "no such table: %T", pName);
|
|
}else{
|
|
sqliteErrorMsg(pParse, "no tables specified");
|
|
}
|
|
rc = 1;
|
|
}
|
|
}
|
|
}
|
|
sqliteExprListDelete(pEList);
|
|
p->pEList = pNew;
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** This routine recursively unlinks the Select.pSrc.a[].pTab pointers
|
|
** in a select structure. It just sets the pointers to NULL. This
|
|
** routine is recursive in the sense that if the Select.pSrc.a[].pSelect
|
|
** pointer is not NULL, this routine is called recursively on that pointer.
|
|
**
|
|
** This routine is called on the Select structure that defines a
|
|
** VIEW in order to undo any bindings to tables. This is necessary
|
|
** because those tables might be DROPed by a subsequent SQL command.
|
|
** If the bindings are not removed, then the Select.pSrc->a[].pTab field
|
|
** will be left pointing to a deallocated Table structure after the
|
|
** DROP and a coredump will occur the next time the VIEW is used.
|
|
*/
|
|
void sqliteSelectUnbind(Select *p){
|
|
int i;
|
|
SrcList *pSrc = p->pSrc;
|
|
Table *pTab;
|
|
if( p==0 ) return;
|
|
for(i=0; i<pSrc->nSrc; i++){
|
|
if( (pTab = pSrc->a[i].pTab)!=0 ){
|
|
if( pTab->isTransient ){
|
|
sqliteDeleteTable(0, pTab);
|
|
}
|
|
pSrc->a[i].pTab = 0;
|
|
if( pSrc->a[i].pSelect ){
|
|
sqliteSelectUnbind(pSrc->a[i].pSelect);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
** This routine associates entries in an ORDER BY expression list with
|
|
** columns in a result. For each ORDER BY expression, the opcode of
|
|
** the top-level node is changed to TK_COLUMN and the iColumn value of
|
|
** the top-level node is filled in with column number and the iTable
|
|
** value of the top-level node is filled with iTable parameter.
|
|
**
|
|
** If there are prior SELECT clauses, they are processed first. A match
|
|
** in an earlier SELECT takes precedence over a later SELECT.
|
|
**
|
|
** Any entry that does not match is flagged as an error. The number
|
|
** of errors is returned.
|
|
**
|
|
** This routine does NOT correctly initialize the Expr.dataType field
|
|
** of the ORDER BY expressions. The multiSelectSortOrder() routine
|
|
** must be called to do that after the individual select statements
|
|
** have all been analyzed. This routine is unable to compute Expr.dataType
|
|
** because it must be called before the individual select statements
|
|
** have been analyzed.
|
|
*/
|
|
static int matchOrderbyToColumn(
|
|
Parse *pParse, /* A place to leave error messages */
|
|
Select *pSelect, /* Match to result columns of this SELECT */
|
|
ExprList *pOrderBy, /* The ORDER BY values to match against columns */
|
|
int iTable, /* Insert this value in iTable */
|
|
int mustComplete /* If TRUE all ORDER BYs must match */
|
|
){
|
|
int nErr = 0;
|
|
int i, j;
|
|
ExprList *pEList;
|
|
|
|
if( pSelect==0 || pOrderBy==0 ) return 1;
|
|
if( mustComplete ){
|
|
for(i=0; i<pOrderBy->nExpr; i++){ pOrderBy->a[i].done = 0; }
|
|
}
|
|
if( fillInColumnList(pParse, pSelect) ){
|
|
return 1;
|
|
}
|
|
if( pSelect->pPrior ){
|
|
if( matchOrderbyToColumn(pParse, pSelect->pPrior, pOrderBy, iTable, 0) ){
|
|
return 1;
|
|
}
|
|
}
|
|
pEList = pSelect->pEList;
|
|
for(i=0; i<pOrderBy->nExpr; i++){
|
|
Expr *pE = pOrderBy->a[i].pExpr;
|
|
int iCol = -1;
|
|
if( pOrderBy->a[i].done ) continue;
|
|
if( sqliteExprIsInteger(pE, &iCol) ){
|
|
if( iCol<=0 || iCol>pEList->nExpr ){
|
|
sqliteErrorMsg(pParse,
|
|
"ORDER BY position %d should be between 1 and %d",
|
|
iCol, pEList->nExpr);
|
|
nErr++;
|
|
break;
|
|
}
|
|
if( !mustComplete ) continue;
|
|
iCol--;
|
|
}
|
|
for(j=0; iCol<0 && j<pEList->nExpr; j++){
|
|
if( pEList->a[j].zName && (pE->op==TK_ID || pE->op==TK_STRING) ){
|
|
char *zName, *zLabel;
|
|
zName = pEList->a[j].zName;
|
|
assert( pE->token.z );
|
|
zLabel = sqliteStrNDup(pE->token.z, pE->token.n);
|
|
sqliteDequote(zLabel);
|
|
if( sqliteStrICmp(zName, zLabel)==0 ){
|
|
iCol = j;
|
|
}
|
|
sqliteFree(zLabel);
|
|
}
|
|
if( iCol<0 && sqliteExprCompare(pE, pEList->a[j].pExpr) ){
|
|
iCol = j;
|
|
}
|
|
}
|
|
if( iCol>=0 ){
|
|
pE->op = TK_COLUMN;
|
|
pE->iColumn = iCol;
|
|
pE->iTable = iTable;
|
|
pOrderBy->a[i].done = 1;
|
|
}
|
|
if( iCol<0 && mustComplete ){
|
|
sqliteErrorMsg(pParse,
|
|
"ORDER BY term number %d does not match any result column", i+1);
|
|
nErr++;
|
|
break;
|
|
}
|
|
}
|
|
return nErr;
|
|
}
|
|
|
|
/*
|
|
** Get a VDBE for the given parser context. Create a new one if necessary.
|
|
** If an error occurs, return NULL and leave a message in pParse.
|
|
*/
|
|
Vdbe *sqliteGetVdbe(Parse *pParse){
|
|
Vdbe *v = pParse->pVdbe;
|
|
if( v==0 ){
|
|
v = pParse->pVdbe = sqliteVdbeCreate(pParse->db);
|
|
}
|
|
return v;
|
|
}
|
|
|
|
/*
|
|
** This routine sets the Expr.dataType field on all elements of
|
|
** the pOrderBy expression list. The pOrderBy list will have been
|
|
** set up by matchOrderbyToColumn(). Hence each expression has
|
|
** a TK_COLUMN as its root node. The Expr.iColumn refers to a
|
|
** column in the result set. The datatype is set to SQLITE_SO_TEXT
|
|
** if the corresponding column in p and every SELECT to the left of
|
|
** p has a datatype of SQLITE_SO_TEXT. If the cooressponding column
|
|
** in p or any of the left SELECTs is SQLITE_SO_NUM, then the datatype
|
|
** of the order-by expression is set to SQLITE_SO_NUM.
|
|
**
|
|
** Examples:
|
|
**
|
|
** CREATE TABLE one(a INTEGER, b TEXT);
|
|
** CREATE TABLE two(c VARCHAR(5), d FLOAT);
|
|
**
|
|
** SELECT b, b FROM one UNION SELECT d, c FROM two ORDER BY 1, 2;
|
|
**
|
|
** The primary sort key will use SQLITE_SO_NUM because the "d" in
|
|
** the second SELECT is numeric. The 1st column of the first SELECT
|
|
** is text but that does not matter because a numeric always overrides
|
|
** a text.
|
|
**
|
|
** The secondary key will use the SQLITE_SO_TEXT sort order because
|
|
** both the (second) "b" in the first SELECT and the "c" in the second
|
|
** SELECT have a datatype of text.
|
|
*/
|
|
static void multiSelectSortOrder(Select *p, ExprList *pOrderBy){
|
|
int i;
|
|
ExprList *pEList;
|
|
if( pOrderBy==0 ) return;
|
|
if( p==0 ){
|
|
for(i=0; i<pOrderBy->nExpr; i++){
|
|
pOrderBy->a[i].pExpr->dataType = SQLITE_SO_TEXT;
|
|
}
|
|
return;
|
|
}
|
|
multiSelectSortOrder(p->pPrior, pOrderBy);
|
|
pEList = p->pEList;
|
|
for(i=0; i<pOrderBy->nExpr; i++){
|
|
Expr *pE = pOrderBy->a[i].pExpr;
|
|
if( pE->dataType==SQLITE_SO_NUM ) continue;
|
|
assert( pE->iColumn>=0 );
|
|
if( pEList->nExpr>pE->iColumn ){
|
|
pE->dataType = sqliteExprType(pEList->a[pE->iColumn].pExpr);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Compute the iLimit and iOffset fields of the SELECT based on the
|
|
** nLimit and nOffset fields. nLimit and nOffset hold the integers
|
|
** that appear in the original SQL statement after the LIMIT and OFFSET
|
|
** keywords. Or that hold -1 and 0 if those keywords are omitted.
|
|
** iLimit and iOffset are the integer memory register numbers for
|
|
** counters used to compute the limit and offset. If there is no
|
|
** limit and/or offset, then iLimit and iOffset are negative.
|
|
**
|
|
** This routine changes the values if iLimit and iOffset only if
|
|
** a limit or offset is defined by nLimit and nOffset. iLimit and
|
|
** iOffset should have been preset to appropriate default values
|
|
** (usually but not always -1) prior to calling this routine.
|
|
** Only if nLimit>=0 or nOffset>0 do the limit registers get
|
|
** redefined. The UNION ALL operator uses this property to force
|
|
** the reuse of the same limit and offset registers across multiple
|
|
** SELECT statements.
|
|
*/
|
|
static void computeLimitRegisters(Parse *pParse, Select *p){
|
|
/*
|
|
** If the comparison is p->nLimit>0 then "LIMIT 0" shows
|
|
** all rows. It is the same as no limit. If the comparision is
|
|
** p->nLimit>=0 then "LIMIT 0" show no rows at all.
|
|
** "LIMIT -1" always shows all rows. There is some
|
|
** contraversy about what the correct behavior should be.
|
|
** The current implementation interprets "LIMIT 0" to mean
|
|
** no rows.
|
|
*/
|
|
if( p->nLimit>=0 ){
|
|
int iMem = pParse->nMem++;
|
|
Vdbe *v = sqliteGetVdbe(pParse);
|
|
if( v==0 ) return;
|
|
sqliteVdbeAddOp(v, OP_Integer, -p->nLimit, 0);
|
|
sqliteVdbeAddOp(v, OP_MemStore, iMem, 1);
|
|
p->iLimit = iMem;
|
|
}
|
|
if( p->nOffset>0 ){
|
|
int iMem = pParse->nMem++;
|
|
Vdbe *v = sqliteGetVdbe(pParse);
|
|
if( v==0 ) return;
|
|
sqliteVdbeAddOp(v, OP_Integer, -p->nOffset, 0);
|
|
sqliteVdbeAddOp(v, OP_MemStore, iMem, 1);
|
|
p->iOffset = iMem;
|
|
}
|
|
}
|
|
|
|
/*
|
|
** This routine is called to process a query that is really the union
|
|
** or intersection of two or more separate queries.
|
|
**
|
|
** "p" points to the right-most of the two queries. the query on the
|
|
** left is p->pPrior. The left query could also be a compound query
|
|
** in which case this routine will be called recursively.
|
|
**
|
|
** The results of the total query are to be written into a destination
|
|
** of type eDest with parameter iParm.
|
|
**
|
|
** Example 1: Consider a three-way compound SQL statement.
|
|
**
|
|
** SELECT a FROM t1 UNION SELECT b FROM t2 UNION SELECT c FROM t3
|
|
**
|
|
** This statement is parsed up as follows:
|
|
**
|
|
** SELECT c FROM t3
|
|
** |
|
|
** `-----> SELECT b FROM t2
|
|
** |
|
|
** `------> SELECT a FROM t1
|
|
**
|
|
** The arrows in the diagram above represent the Select.pPrior pointer.
|
|
** So if this routine is called with p equal to the t3 query, then
|
|
** pPrior will be the t2 query. p->op will be TK_UNION in this case.
|
|
**
|
|
** Notice that because of the way SQLite parses compound SELECTs, the
|
|
** individual selects always group from left to right.
|
|
*/
|
|
static int multiSelect(Parse *pParse, Select *p, int eDest, int iParm){
|
|
int rc; /* Success code from a subroutine */
|
|
Select *pPrior; /* Another SELECT immediately to our left */
|
|
Vdbe *v; /* Generate code to this VDBE */
|
|
|
|
/* Make sure there is no ORDER BY or LIMIT clause on prior SELECTs. Only
|
|
** the last SELECT in the series may have an ORDER BY or LIMIT.
|
|
*/
|
|
if( p==0 || p->pPrior==0 ) return 1;
|
|
pPrior = p->pPrior;
|
|
if( pPrior->pOrderBy ){
|
|
sqliteErrorMsg(pParse,"ORDER BY clause should come after %s not before",
|
|
selectOpName(p->op));
|
|
return 1;
|
|
}
|
|
if( pPrior->nLimit>=0 || pPrior->nOffset>0 ){
|
|
sqliteErrorMsg(pParse,"LIMIT clause should come after %s not before",
|
|
selectOpName(p->op));
|
|
return 1;
|
|
}
|
|
|
|
/* Make sure we have a valid query engine. If not, create a new one.
|
|
*/
|
|
v = sqliteGetVdbe(pParse);
|
|
if( v==0 ) return 1;
|
|
|
|
/* Create the destination temporary table if necessary
|
|
*/
|
|
if( eDest==SRT_TempTable ){
|
|
sqliteVdbeAddOp(v, OP_OpenTemp, iParm, 0);
|
|
eDest = SRT_Table;
|
|
}
|
|
|
|
/* Generate code for the left and right SELECT statements.
|
|
*/
|
|
switch( p->op ){
|
|
case TK_ALL: {
|
|
if( p->pOrderBy==0 ){
|
|
pPrior->nLimit = p->nLimit;
|
|
pPrior->nOffset = p->nOffset;
|
|
rc = sqliteSelect(pParse, pPrior, eDest, iParm, 0, 0, 0);
|
|
if( rc ) return rc;
|
|
p->pPrior = 0;
|
|
p->iLimit = pPrior->iLimit;
|
|
p->iOffset = pPrior->iOffset;
|
|
p->nLimit = -1;
|
|
p->nOffset = 0;
|
|
rc = sqliteSelect(pParse, p, eDest, iParm, 0, 0, 0);
|
|
p->pPrior = pPrior;
|
|
if( rc ) return rc;
|
|
break;
|
|
}
|
|
/* For UNION ALL ... ORDER BY fall through to the next case */
|
|
}
|
|
case TK_EXCEPT:
|
|
case TK_UNION: {
|
|
int unionTab; /* Cursor number of the temporary table holding result */
|
|
int op; /* One of the SRT_ operations to apply to self */
|
|
int priorOp; /* The SRT_ operation to apply to prior selects */
|
|
int nLimit, nOffset; /* Saved values of p->nLimit and p->nOffset */
|
|
ExprList *pOrderBy; /* The ORDER BY clause for the right SELECT */
|
|
|
|
priorOp = p->op==TK_ALL ? SRT_Table : SRT_Union;
|
|
if( eDest==priorOp && p->pOrderBy==0 && p->nLimit<0 && p->nOffset==0 ){
|
|
/* We can reuse a temporary table generated by a SELECT to our
|
|
** right.
|
|
*/
|
|
unionTab = iParm;
|
|
}else{
|
|
/* We will need to create our own temporary table to hold the
|
|
** intermediate results.
|
|
*/
|
|
unionTab = pParse->nTab++;
|
|
if( p->pOrderBy
|
|
&& matchOrderbyToColumn(pParse, p, p->pOrderBy, unionTab, 1) ){
|
|
return 1;
|
|
}
|
|
if( p->op!=TK_ALL ){
|
|
sqliteVdbeAddOp(v, OP_OpenTemp, unionTab, 1);
|
|
sqliteVdbeAddOp(v, OP_KeyAsData, unionTab, 1);
|
|
}else{
|
|
sqliteVdbeAddOp(v, OP_OpenTemp, unionTab, 0);
|
|
}
|
|
}
|
|
|
|
/* Code the SELECT statements to our left
|
|
*/
|
|
rc = sqliteSelect(pParse, pPrior, priorOp, unionTab, 0, 0, 0);
|
|
if( rc ) return rc;
|
|
|
|
/* Code the current SELECT statement
|
|
*/
|
|
switch( p->op ){
|
|
case TK_EXCEPT: op = SRT_Except; break;
|
|
case TK_UNION: op = SRT_Union; break;
|
|
case TK_ALL: op = SRT_Table; break;
|
|
}
|
|
p->pPrior = 0;
|
|
pOrderBy = p->pOrderBy;
|
|
p->pOrderBy = 0;
|
|
nLimit = p->nLimit;
|
|
p->nLimit = -1;
|
|
nOffset = p->nOffset;
|
|
p->nOffset = 0;
|
|
rc = sqliteSelect(pParse, p, op, unionTab, 0, 0, 0);
|
|
p->pPrior = pPrior;
|
|
p->pOrderBy = pOrderBy;
|
|
p->nLimit = nLimit;
|
|
p->nOffset = nOffset;
|
|
if( rc ) return rc;
|
|
|
|
/* Convert the data in the temporary table into whatever form
|
|
** it is that we currently need.
|
|
*/
|
|
if( eDest!=priorOp || unionTab!=iParm ){
|
|
int iCont, iBreak, iStart;
|
|
assert( p->pEList );
|
|
if( eDest==SRT_Callback ){
|
|
generateColumnNames(pParse, 0, p->pEList);
|
|
generateColumnTypes(pParse, p->pSrc, p->pEList);
|
|
}
|
|
iBreak = sqliteVdbeMakeLabel(v);
|
|
iCont = sqliteVdbeMakeLabel(v);
|
|
sqliteVdbeAddOp(v, OP_Rewind, unionTab, iBreak);
|
|
computeLimitRegisters(pParse, p);
|
|
iStart = sqliteVdbeCurrentAddr(v);
|
|
multiSelectSortOrder(p, p->pOrderBy);
|
|
rc = selectInnerLoop(pParse, p, p->pEList, unionTab, p->pEList->nExpr,
|
|
p->pOrderBy, -1, eDest, iParm,
|
|
iCont, iBreak);
|
|
if( rc ) return 1;
|
|
sqliteVdbeResolveLabel(v, iCont);
|
|
sqliteVdbeAddOp(v, OP_Next, unionTab, iStart);
|
|
sqliteVdbeResolveLabel(v, iBreak);
|
|
sqliteVdbeAddOp(v, OP_Close, unionTab, 0);
|
|
if( p->pOrderBy ){
|
|
generateSortTail(p, v, p->pEList->nExpr, eDest, iParm);
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
case TK_INTERSECT: {
|
|
int tab1, tab2;
|
|
int iCont, iBreak, iStart;
|
|
int nLimit, nOffset;
|
|
|
|
/* INTERSECT is different from the others since it requires
|
|
** two temporary tables. Hence it has its own case. Begin
|
|
** by allocating the tables we will need.
|
|
*/
|
|
tab1 = pParse->nTab++;
|
|
tab2 = pParse->nTab++;
|
|
if( p->pOrderBy && matchOrderbyToColumn(pParse,p,p->pOrderBy,tab1,1) ){
|
|
return 1;
|
|
}
|
|
sqliteVdbeAddOp(v, OP_OpenTemp, tab1, 1);
|
|
sqliteVdbeAddOp(v, OP_KeyAsData, tab1, 1);
|
|
|
|
/* Code the SELECTs to our left into temporary table "tab1".
|
|
*/
|
|
rc = sqliteSelect(pParse, pPrior, SRT_Union, tab1, 0, 0, 0);
|
|
if( rc ) return rc;
|
|
|
|
/* Code the current SELECT into temporary table "tab2"
|
|
*/
|
|
sqliteVdbeAddOp(v, OP_OpenTemp, tab2, 1);
|
|
sqliteVdbeAddOp(v, OP_KeyAsData, tab2, 1);
|
|
p->pPrior = 0;
|
|
nLimit = p->nLimit;
|
|
p->nLimit = -1;
|
|
nOffset = p->nOffset;
|
|
p->nOffset = 0;
|
|
rc = sqliteSelect(pParse, p, SRT_Union, tab2, 0, 0, 0);
|
|
p->pPrior = pPrior;
|
|
p->nLimit = nLimit;
|
|
p->nOffset = nOffset;
|
|
if( rc ) return rc;
|
|
|
|
/* Generate code to take the intersection of the two temporary
|
|
** tables.
|
|
*/
|
|
assert( p->pEList );
|
|
if( eDest==SRT_Callback ){
|
|
generateColumnNames(pParse, 0, p->pEList);
|
|
generateColumnTypes(pParse, p->pSrc, p->pEList);
|
|
}
|
|
iBreak = sqliteVdbeMakeLabel(v);
|
|
iCont = sqliteVdbeMakeLabel(v);
|
|
sqliteVdbeAddOp(v, OP_Rewind, tab1, iBreak);
|
|
computeLimitRegisters(pParse, p);
|
|
iStart = sqliteVdbeAddOp(v, OP_FullKey, tab1, 0);
|
|
sqliteVdbeAddOp(v, OP_NotFound, tab2, iCont);
|
|
multiSelectSortOrder(p, p->pOrderBy);
|
|
rc = selectInnerLoop(pParse, p, p->pEList, tab1, p->pEList->nExpr,
|
|
p->pOrderBy, -1, eDest, iParm,
|
|
iCont, iBreak);
|
|
if( rc ) return 1;
|
|
sqliteVdbeResolveLabel(v, iCont);
|
|
sqliteVdbeAddOp(v, OP_Next, tab1, iStart);
|
|
sqliteVdbeResolveLabel(v, iBreak);
|
|
sqliteVdbeAddOp(v, OP_Close, tab2, 0);
|
|
sqliteVdbeAddOp(v, OP_Close, tab1, 0);
|
|
if( p->pOrderBy ){
|
|
generateSortTail(p, v, p->pEList->nExpr, eDest, iParm);
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
assert( p->pEList && pPrior->pEList );
|
|
if( p->pEList->nExpr!=pPrior->pEList->nExpr ){
|
|
sqliteErrorMsg(pParse, "SELECTs to the left and right of %s"
|
|
" do not have the same number of result columns", selectOpName(p->op));
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
** Scan through the expression pExpr. Replace every reference to
|
|
** a column in table number iTable with a copy of the iColumn-th
|
|
** entry in pEList. (But leave references to the ROWID column
|
|
** unchanged.)
|
|
**
|
|
** This routine is part of the flattening procedure. A subquery
|
|
** whose result set is defined by pEList appears as entry in the
|
|
** FROM clause of a SELECT such that the VDBE cursor assigned to that
|
|
** FORM clause entry is iTable. This routine make the necessary
|
|
** changes to pExpr so that it refers directly to the source table
|
|
** of the subquery rather the result set of the subquery.
|
|
*/
|
|
static void substExprList(ExprList*,int,ExprList*); /* Forward Decl */
|
|
static void substExpr(Expr *pExpr, int iTable, ExprList *pEList){
|
|
if( pExpr==0 ) return;
|
|
if( pExpr->op==TK_COLUMN && pExpr->iTable==iTable ){
|
|
if( pExpr->iColumn<0 ){
|
|
pExpr->op = TK_NULL;
|
|
}else{
|
|
Expr *pNew;
|
|
assert( pEList!=0 && pExpr->iColumn<pEList->nExpr );
|
|
assert( pExpr->pLeft==0 && pExpr->pRight==0 && pExpr->pList==0 );
|
|
pNew = pEList->a[pExpr->iColumn].pExpr;
|
|
assert( pNew!=0 );
|
|
pExpr->op = pNew->op;
|
|
pExpr->dataType = pNew->dataType;
|
|
assert( pExpr->pLeft==0 );
|
|
pExpr->pLeft = sqliteExprDup(pNew->pLeft);
|
|
assert( pExpr->pRight==0 );
|
|
pExpr->pRight = sqliteExprDup(pNew->pRight);
|
|
assert( pExpr->pList==0 );
|
|
pExpr->pList = sqliteExprListDup(pNew->pList);
|
|
pExpr->iTable = pNew->iTable;
|
|
pExpr->iColumn = pNew->iColumn;
|
|
pExpr->iAgg = pNew->iAgg;
|
|
sqliteTokenCopy(&pExpr->token, &pNew->token);
|
|
sqliteTokenCopy(&pExpr->span, &pNew->span);
|
|
}
|
|
}else{
|
|
substExpr(pExpr->pLeft, iTable, pEList);
|
|
substExpr(pExpr->pRight, iTable, pEList);
|
|
substExprList(pExpr->pList, iTable, pEList);
|
|
}
|
|
}
|
|
static void
|
|
substExprList(ExprList *pList, int iTable, ExprList *pEList){
|
|
int i;
|
|
if( pList==0 ) return;
|
|
for(i=0; i<pList->nExpr; i++){
|
|
substExpr(pList->a[i].pExpr, iTable, pEList);
|
|
}
|
|
}
|
|
|
|
/*
|
|
** This routine attempts to flatten subqueries in order to speed
|
|
** execution. It returns 1 if it makes changes and 0 if no flattening
|
|
** occurs.
|
|
**
|
|
** To understand the concept of flattening, consider the following
|
|
** query:
|
|
**
|
|
** SELECT a FROM (SELECT x+y AS a FROM t1 WHERE z<100) WHERE a>5
|
|
**
|
|
** The default way of implementing this query is to execute the
|
|
** subquery first and store the results in a temporary table, then
|
|
** run the outer query on that temporary table. This requires two
|
|
** passes over the data. Furthermore, because the temporary table
|
|
** has no indices, the WHERE clause on the outer query cannot be
|
|
** optimized.
|
|
**
|
|
** This routine attempts to rewrite queries such as the above into
|
|
** a single flat select, like this:
|
|
**
|
|
** SELECT x+y AS a FROM t1 WHERE z<100 AND a>5
|
|
**
|
|
** The code generated for this simpification gives the same result
|
|
** but only has to scan the data once. And because indices might
|
|
** exist on the table t1, a complete scan of the data might be
|
|
** avoided.
|
|
**
|
|
** Flattening is only attempted if all of the following are true:
|
|
**
|
|
** (1) The subquery and the outer query do not both use aggregates.
|
|
**
|
|
** (2) The subquery is not an aggregate or the outer query is not a join.
|
|
**
|
|
** (3) The subquery is not the right operand of a left outer join, or
|
|
** the subquery is not itself a join. (Ticket #306)
|
|
**
|
|
** (4) The subquery is not DISTINCT or the outer query is not a join.
|
|
**
|
|
** (5) The subquery is not DISTINCT or the outer query does not use
|
|
** aggregates.
|
|
**
|
|
** (6) The subquery does not use aggregates or the outer query is not
|
|
** DISTINCT.
|
|
**
|
|
** (7) The subquery has a FROM clause.
|
|
**
|
|
** (8) The subquery does not use LIMIT or the outer query is not a join.
|
|
**
|
|
** (9) The subquery does not use LIMIT or the outer query does not use
|
|
** aggregates.
|
|
**
|
|
** (10) The subquery does not use aggregates or the outer query does not
|
|
** use LIMIT.
|
|
**
|
|
** (11) The subquery and the outer query do not both have ORDER BY clauses.
|
|
**
|
|
** (12) The subquery is not the right term of a LEFT OUTER JOIN or the
|
|
** subquery has no WHERE clause. (added by ticket #350)
|
|
**
|
|
** In this routine, the "p" parameter is a pointer to the outer query.
|
|
** The subquery is p->pSrc->a[iFrom]. isAgg is true if the outer query
|
|
** uses aggregates and subqueryIsAgg is true if the subquery uses aggregates.
|
|
**
|
|
** If flattening is not attempted, this routine is a no-op and returns 0.
|
|
** If flattening is attempted this routine returns 1.
|
|
**
|
|
** All of the expression analysis must occur on both the outer query and
|
|
** the subquery before this routine runs.
|
|
*/
|
|
static int flattenSubquery(
|
|
Parse *pParse, /* The parsing context */
|
|
Select *p, /* The parent or outer SELECT statement */
|
|
int iFrom, /* Index in p->pSrc->a[] of the inner subquery */
|
|
int isAgg, /* True if outer SELECT uses aggregate functions */
|
|
int subqueryIsAgg /* True if the subquery uses aggregate functions */
|
|
){
|
|
Select *pSub; /* The inner query or "subquery" */
|
|
SrcList *pSrc; /* The FROM clause of the outer query */
|
|
SrcList *pSubSrc; /* The FROM clause of the subquery */
|
|
ExprList *pList; /* The result set of the outer query */
|
|
int iParent; /* VDBE cursor number of the pSub result set temp table */
|
|
int i;
|
|
Expr *pWhere;
|
|
|
|
/* Check to see if flattening is permitted. Return 0 if not.
|
|
*/
|
|
if( p==0 ) return 0;
|
|
pSrc = p->pSrc;
|
|
assert( pSrc && iFrom>=0 && iFrom<pSrc->nSrc );
|
|
pSub = pSrc->a[iFrom].pSelect;
|
|
assert( pSub!=0 );
|
|
if( isAgg && subqueryIsAgg ) return 0;
|
|
if( subqueryIsAgg && pSrc->nSrc>1 ) return 0;
|
|
pSubSrc = pSub->pSrc;
|
|
assert( pSubSrc );
|
|
if( pSubSrc->nSrc==0 ) return 0;
|
|
if( (pSub->isDistinct || pSub->nLimit>=0) && (pSrc->nSrc>1 || isAgg) ){
|
|
return 0;
|
|
}
|
|
if( (p->isDistinct || p->nLimit>=0) && subqueryIsAgg ) return 0;
|
|
if( p->pOrderBy && pSub->pOrderBy ) return 0;
|
|
|
|
/* Restriction 3: If the subquery is a join, make sure the subquery is
|
|
** not used as the right operand of an outer join. Examples of why this
|
|
** is not allowed:
|
|
**
|
|
** t1 LEFT OUTER JOIN (t2 JOIN t3)
|
|
**
|
|
** If we flatten the above, we would get
|
|
**
|
|
** (t1 LEFT OUTER JOIN t2) JOIN t3
|
|
**
|
|
** which is not at all the same thing.
|
|
*/
|
|
if( pSubSrc->nSrc>1 && iFrom>0 && (pSrc->a[iFrom-1].jointype & JT_OUTER)!=0 ){
|
|
return 0;
|
|
}
|
|
|
|
/* Restriction 12: If the subquery is the right operand of a left outer
|
|
** join, make sure the subquery has no WHERE clause.
|
|
** An examples of why this is not allowed:
|
|
**
|
|
** t1 LEFT OUTER JOIN (SELECT * FROM t2 WHERE t2.x>0)
|
|
**
|
|
** If we flatten the above, we would get
|
|
**
|
|
** (t1 LEFT OUTER JOIN t2) WHERE t2.x>0
|
|
**
|
|
** But the t2.x>0 test will always fail on a NULL row of t2, which
|
|
** effectively converts the OUTER JOIN into an INNER JOIN.
|
|
*/
|
|
if( iFrom>0 && (pSrc->a[iFrom-1].jointype & JT_OUTER)!=0
|
|
&& pSub->pWhere!=0 ){
|
|
return 0;
|
|
}
|
|
|
|
/* If we reach this point, it means flattening is permitted for the
|
|
** iFrom-th entry of the FROM clause in the outer query.
|
|
*/
|
|
|
|
/* Move all of the FROM elements of the subquery into the
|
|
** the FROM clause of the outer query. Before doing this, remember
|
|
** the cursor number for the original outer query FROM element in
|
|
** iParent. The iParent cursor will never be used. Subsequent code
|
|
** will scan expressions looking for iParent references and replace
|
|
** those references with expressions that resolve to the subquery FROM
|
|
** elements we are now copying in.
|
|
*/
|
|
iParent = pSrc->a[iFrom].iCursor;
|
|
{
|
|
int nSubSrc = pSubSrc->nSrc;
|
|
int jointype = pSrc->a[iFrom].jointype;
|
|
|
|
if( pSrc->a[iFrom].pTab && pSrc->a[iFrom].pTab->isTransient ){
|
|
sqliteDeleteTable(0, pSrc->a[iFrom].pTab);
|
|
}
|
|
sqliteFree(pSrc->a[iFrom].zDatabase);
|
|
sqliteFree(pSrc->a[iFrom].zName);
|
|
sqliteFree(pSrc->a[iFrom].zAlias);
|
|
if( nSubSrc>1 ){
|
|
int extra = nSubSrc - 1;
|
|
for(i=1; i<nSubSrc; i++){
|
|
pSrc = sqliteSrcListAppend(pSrc, 0, 0);
|
|
}
|
|
p->pSrc = pSrc;
|
|
for(i=pSrc->nSrc-1; i-extra>=iFrom; i--){
|
|
pSrc->a[i] = pSrc->a[i-extra];
|
|
}
|
|
}
|
|
for(i=0; i<nSubSrc; i++){
|
|
pSrc->a[i+iFrom] = pSubSrc->a[i];
|
|
memset(&pSubSrc->a[i], 0, sizeof(pSubSrc->a[i]));
|
|
}
|
|
pSrc->a[iFrom+nSubSrc-1].jointype = jointype;
|
|
}
|
|
|
|
/* Now begin substituting subquery result set expressions for
|
|
** references to the iParent in the outer query.
|
|
**
|
|
** Example:
|
|
**
|
|
** SELECT a+5, b*10 FROM (SELECT x*3 AS a, y+10 AS b FROM t1) WHERE a>b;
|
|
** \ \_____________ subquery __________/ /
|
|
** \_____________________ outer query ______________________________/
|
|
**
|
|
** We look at every expression in the outer query and every place we see
|
|
** "a" we substitute "x*3" and every place we see "b" we substitute "y+10".
|
|
*/
|
|
substExprList(p->pEList, iParent, pSub->pEList);
|
|
pList = p->pEList;
|
|
for(i=0; i<pList->nExpr; i++){
|
|
Expr *pExpr;
|
|
if( pList->a[i].zName==0 && (pExpr = pList->a[i].pExpr)->span.z!=0 ){
|
|
pList->a[i].zName = sqliteStrNDup(pExpr->span.z, pExpr->span.n);
|
|
}
|
|
}
|
|
if( isAgg ){
|
|
substExprList(p->pGroupBy, iParent, pSub->pEList);
|
|
substExpr(p->pHaving, iParent, pSub->pEList);
|
|
}
|
|
if( pSub->pOrderBy ){
|
|
assert( p->pOrderBy==0 );
|
|
p->pOrderBy = pSub->pOrderBy;
|
|
pSub->pOrderBy = 0;
|
|
}else if( p->pOrderBy ){
|
|
substExprList(p->pOrderBy, iParent, pSub->pEList);
|
|
}
|
|
if( pSub->pWhere ){
|
|
pWhere = sqliteExprDup(pSub->pWhere);
|
|
}else{
|
|
pWhere = 0;
|
|
}
|
|
if( subqueryIsAgg ){
|
|
assert( p->pHaving==0 );
|
|
p->pHaving = p->pWhere;
|
|
p->pWhere = pWhere;
|
|
substExpr(p->pHaving, iParent, pSub->pEList);
|
|
if( pSub->pHaving ){
|
|
Expr *pHaving = sqliteExprDup(pSub->pHaving);
|
|
if( p->pHaving ){
|
|
p->pHaving = sqliteExpr(TK_AND, p->pHaving, pHaving, 0);
|
|
}else{
|
|
p->pHaving = pHaving;
|
|
}
|
|
}
|
|
assert( p->pGroupBy==0 );
|
|
p->pGroupBy = sqliteExprListDup(pSub->pGroupBy);
|
|
}else if( p->pWhere==0 ){
|
|
p->pWhere = pWhere;
|
|
}else{
|
|
substExpr(p->pWhere, iParent, pSub->pEList);
|
|
if( pWhere ){
|
|
p->pWhere = sqliteExpr(TK_AND, p->pWhere, pWhere, 0);
|
|
}
|
|
}
|
|
|
|
/* The flattened query is distinct if either the inner or the
|
|
** outer query is distinct.
|
|
*/
|
|
p->isDistinct = p->isDistinct || pSub->isDistinct;
|
|
|
|
/* Transfer the limit expression from the subquery to the outer
|
|
** query.
|
|
*/
|
|
if( pSub->nLimit>=0 ){
|
|
if( p->nLimit<0 ){
|
|
p->nLimit = pSub->nLimit;
|
|
}else if( p->nLimit+p->nOffset > pSub->nLimit+pSub->nOffset ){
|
|
p->nLimit = pSub->nLimit + pSub->nOffset - p->nOffset;
|
|
}
|
|
}
|
|
p->nOffset += pSub->nOffset;
|
|
|
|
/* Finially, delete what is left of the subquery and return
|
|
** success.
|
|
*/
|
|
sqliteSelectDelete(pSub);
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
** Analyze the SELECT statement passed in as an argument to see if it
|
|
** is a simple min() or max() query. If it is and this query can be
|
|
** satisfied using a single seek to the beginning or end of an index,
|
|
** then generate the code for this SELECT and return 1. If this is not a
|
|
** simple min() or max() query, then return 0;
|
|
**
|
|
** A simply min() or max() query looks like this:
|
|
**
|
|
** SELECT min(a) FROM table;
|
|
** SELECT max(a) FROM table;
|
|
**
|
|
** The query may have only a single table in its FROM argument. There
|
|
** can be no GROUP BY or HAVING or WHERE clauses. The result set must
|
|
** be the min() or max() of a single column of the table. The column
|
|
** in the min() or max() function must be indexed.
|
|
**
|
|
** The parameters to this routine are the same as for sqliteSelect().
|
|
** See the header comment on that routine for additional information.
|
|
*/
|
|
static int simpleMinMaxQuery(Parse *pParse, Select *p, int eDest, int iParm){
|
|
Expr *pExpr;
|
|
int iCol;
|
|
Table *pTab;
|
|
Index *pIdx;
|
|
int base;
|
|
Vdbe *v;
|
|
int seekOp;
|
|
int cont;
|
|
ExprList eList;
|
|
struct ExprList_item eListItem;
|
|
|
|
/* Check to see if this query is a simple min() or max() query. Return
|
|
** zero if it is not.
|
|
*/
|
|
if( p->pGroupBy || p->pHaving || p->pWhere ) return 0;
|
|
if( p->pSrc->nSrc!=1 ) return 0;
|
|
if( p->pEList->nExpr!=1 ) return 0;
|
|
pExpr = p->pEList->a[0].pExpr;
|
|
if( pExpr->op!=TK_AGG_FUNCTION ) return 0;
|
|
if( pExpr->pList==0 || pExpr->pList->nExpr!=1 ) return 0;
|
|
if( pExpr->token.n!=3 ) return 0;
|
|
if( sqliteStrNICmp(pExpr->token.z,"min",3)==0 ){
|
|
seekOp = OP_Rewind;
|
|
}else if( sqliteStrNICmp(pExpr->token.z,"max",3)==0 ){
|
|
seekOp = OP_Last;
|
|
}else{
|
|
return 0;
|
|
}
|
|
pExpr = pExpr->pList->a[0].pExpr;
|
|
if( pExpr->op!=TK_COLUMN ) return 0;
|
|
iCol = pExpr->iColumn;
|
|
pTab = p->pSrc->a[0].pTab;
|
|
|
|
/* If we get to here, it means the query is of the correct form.
|
|
** Check to make sure we have an index and make pIdx point to the
|
|
** appropriate index. If the min() or max() is on an INTEGER PRIMARY
|
|
** key column, no index is necessary so set pIdx to NULL. If no
|
|
** usable index is found, return 0.
|
|
*/
|
|
if( iCol<0 ){
|
|
pIdx = 0;
|
|
}else{
|
|
for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
|
|
assert( pIdx->nColumn>=1 );
|
|
if( pIdx->aiColumn[0]==iCol ) break;
|
|
}
|
|
if( pIdx==0 ) return 0;
|
|
}
|
|
|
|
/* Identify column types if we will be using the callback. This
|
|
** step is skipped if the output is going to a table or a memory cell.
|
|
** The column names have already been generated in the calling function.
|
|
*/
|
|
v = sqliteGetVdbe(pParse);
|
|
if( v==0 ) return 0;
|
|
if( eDest==SRT_Callback ){
|
|
generateColumnTypes(pParse, p->pSrc, p->pEList);
|
|
}
|
|
|
|
/* If the output is destined for a temporary table, open that table.
|
|
*/
|
|
if( eDest==SRT_TempTable ){
|
|
sqliteVdbeAddOp(v, OP_OpenTemp, iParm, 0);
|
|
}
|
|
|
|
/* Generating code to find the min or the max. Basically all we have
|
|
** to do is find the first or the last entry in the chosen index. If
|
|
** the min() or max() is on the INTEGER PRIMARY KEY, then find the first
|
|
** or last entry in the main table.
|
|
*/
|
|
sqliteCodeVerifySchema(pParse, pTab->iDb);
|
|
base = p->pSrc->a[0].iCursor;
|
|
computeLimitRegisters(pParse, p);
|
|
sqliteVdbeAddOp(v, OP_Integer, pTab->iDb, 0);
|
|
sqliteVdbeOp3(v, OP_OpenRead, base, pTab->tnum, pTab->zName, 0);
|
|
cont = sqliteVdbeMakeLabel(v);
|
|
if( pIdx==0 ){
|
|
sqliteVdbeAddOp(v, seekOp, base, 0);
|
|
}else{
|
|
sqliteVdbeAddOp(v, OP_Integer, pIdx->iDb, 0);
|
|
sqliteVdbeOp3(v, OP_OpenRead, base+1, pIdx->tnum, pIdx->zName, P3_STATIC);
|
|
sqliteVdbeAddOp(v, seekOp, base+1, 0);
|
|
sqliteVdbeAddOp(v, OP_IdxRecno, base+1, 0);
|
|
sqliteVdbeAddOp(v, OP_Close, base+1, 0);
|
|
sqliteVdbeAddOp(v, OP_MoveTo, base, 0);
|
|
}
|
|
eList.nExpr = 1;
|
|
memset(&eListItem, 0, sizeof(eListItem));
|
|
eList.a = &eListItem;
|
|
eList.a[0].pExpr = pExpr;
|
|
selectInnerLoop(pParse, p, &eList, 0, 0, 0, -1, eDest, iParm, cont, cont);
|
|
sqliteVdbeResolveLabel(v, cont);
|
|
sqliteVdbeAddOp(v, OP_Close, base, 0);
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
** Generate code for the given SELECT statement.
|
|
**
|
|
** The results are distributed in various ways depending on the
|
|
** value of eDest and iParm.
|
|
**
|
|
** eDest Value Result
|
|
** ------------ -------------------------------------------
|
|
** SRT_Callback Invoke the callback for each row of the result.
|
|
**
|
|
** SRT_Mem Store first result in memory cell iParm
|
|
**
|
|
** SRT_Set Store results as keys of a table with cursor iParm
|
|
**
|
|
** SRT_Union Store results as a key in a temporary table iParm
|
|
**
|
|
** SRT_Except Remove results from the temporary table iParm.
|
|
**
|
|
** SRT_Table Store results in temporary table iParm
|
|
**
|
|
** The table above is incomplete. Additional eDist value have be added
|
|
** since this comment was written. See the selectInnerLoop() function for
|
|
** a complete listing of the allowed values of eDest and their meanings.
|
|
**
|
|
** This routine returns the number of errors. If any errors are
|
|
** encountered, then an appropriate error message is left in
|
|
** pParse->zErrMsg.
|
|
**
|
|
** This routine does NOT free the Select structure passed in. The
|
|
** calling function needs to do that.
|
|
**
|
|
** The pParent, parentTab, and *pParentAgg fields are filled in if this
|
|
** SELECT is a subquery. This routine may try to combine this SELECT
|
|
** with its parent to form a single flat query. In so doing, it might
|
|
** change the parent query from a non-aggregate to an aggregate query.
|
|
** For that reason, the pParentAgg flag is passed as a pointer, so it
|
|
** can be changed.
|
|
**
|
|
** Example 1: The meaning of the pParent parameter.
|
|
**
|
|
** SELECT * FROM t1 JOIN (SELECT x, count(*) FROM t2) JOIN t3;
|
|
** \ \_______ subquery _______/ /
|
|
** \ /
|
|
** \____________________ outer query ___________________/
|
|
**
|
|
** This routine is called for the outer query first. For that call,
|
|
** pParent will be NULL. During the processing of the outer query, this
|
|
** routine is called recursively to handle the subquery. For the recursive
|
|
** call, pParent will point to the outer query. Because the subquery is
|
|
** the second element in a three-way join, the parentTab parameter will
|
|
** be 1 (the 2nd value of a 0-indexed array.)
|
|
*/
|
|
int sqliteSelect(
|
|
Parse *pParse, /* The parser context */
|
|
Select *p, /* The SELECT statement being coded. */
|
|
int eDest, /* How to dispose of the results */
|
|
int iParm, /* A parameter used by the eDest disposal method */
|
|
Select *pParent, /* Another SELECT for which this is a sub-query */
|
|
int parentTab, /* Index in pParent->pSrc of this query */
|
|
int *pParentAgg /* True if pParent uses aggregate functions */
|
|
){
|
|
int i;
|
|
WhereInfo *pWInfo;
|
|
Vdbe *v;
|
|
int isAgg = 0; /* True for select lists like "count(*)" */
|
|
ExprList *pEList; /* List of columns to extract. */
|
|
SrcList *pTabList; /* List of tables to select from */
|
|
Expr *pWhere; /* The WHERE clause. May be NULL */
|
|
ExprList *pOrderBy; /* The ORDER BY clause. May be NULL */
|
|
ExprList *pGroupBy; /* The GROUP BY clause. May be NULL */
|
|
Expr *pHaving; /* The HAVING clause. May be NULL */
|
|
int isDistinct; /* True if the DISTINCT keyword is present */
|
|
int distinct; /* Table to use for the distinct set */
|
|
int rc = 1; /* Value to return from this function */
|
|
|
|
if( sqlite_malloc_failed || pParse->nErr || p==0 ) return 1;
|
|
if( sqliteAuthCheck(pParse, SQLITE_SELECT, 0, 0, 0) ) return 1;
|
|
|
|
/* If there is are a sequence of queries, do the earlier ones first.
|
|
*/
|
|
if( p->pPrior ){
|
|
return multiSelect(pParse, p, eDest, iParm);
|
|
}
|
|
|
|
/* Make local copies of the parameters for this query.
|
|
*/
|
|
pTabList = p->pSrc;
|
|
pWhere = p->pWhere;
|
|
pOrderBy = p->pOrderBy;
|
|
pGroupBy = p->pGroupBy;
|
|
pHaving = p->pHaving;
|
|
isDistinct = p->isDistinct;
|
|
|
|
/* Allocate VDBE cursors for each table in the FROM clause
|
|
*/
|
|
sqliteSrcListAssignCursors(pParse, pTabList);
|
|
|
|
/*
|
|
** Do not even attempt to generate any code if we have already seen
|
|
** errors before this routine starts.
|
|
*/
|
|
if( pParse->nErr>0 ) goto select_end;
|
|
|
|
/* Expand any "*" terms in the result set. (For example the "*" in
|
|
** "SELECT * FROM t1") The fillInColumnlist() routine also does some
|
|
** other housekeeping - see the header comment for details.
|
|
*/
|
|
if( fillInColumnList(pParse, p) ){
|
|
goto select_end;
|
|
}
|
|
pWhere = p->pWhere;
|
|
pEList = p->pEList;
|
|
if( pEList==0 ) goto select_end;
|
|
|
|
/* If writing to memory or generating a set
|
|
** only a single column may be output.
|
|
*/
|
|
if( (eDest==SRT_Mem || eDest==SRT_Set) && pEList->nExpr>1 ){
|
|
sqliteErrorMsg(pParse, "only a single result allowed for "
|
|
"a SELECT that is part of an expression");
|
|
goto select_end;
|
|
}
|
|
|
|
/* ORDER BY is ignored for some destinations.
|
|
*/
|
|
switch( eDest ){
|
|
case SRT_Union:
|
|
case SRT_Except:
|
|
case SRT_Discard:
|
|
pOrderBy = 0;
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
|
|
/* At this point, we should have allocated all the cursors that we
|
|
** need to handle subquerys and temporary tables.
|
|
**
|
|
** Resolve the column names and do a semantics check on all the expressions.
|
|
*/
|
|
for(i=0; i<pEList->nExpr; i++){
|
|
if( sqliteExprResolveIds(pParse, pTabList, 0, pEList->a[i].pExpr) ){
|
|
goto select_end;
|
|
}
|
|
if( sqliteExprCheck(pParse, pEList->a[i].pExpr, 1, &isAgg) ){
|
|
goto select_end;
|
|
}
|
|
}
|
|
if( pWhere ){
|
|
if( sqliteExprResolveIds(pParse, pTabList, pEList, pWhere) ){
|
|
goto select_end;
|
|
}
|
|
if( sqliteExprCheck(pParse, pWhere, 0, 0) ){
|
|
goto select_end;
|
|
}
|
|
}
|
|
if( pHaving ){
|
|
if( pGroupBy==0 ){
|
|
sqliteErrorMsg(pParse, "a GROUP BY clause is required before HAVING");
|
|
goto select_end;
|
|
}
|
|
if( sqliteExprResolveIds(pParse, pTabList, pEList, pHaving) ){
|
|
goto select_end;
|
|
}
|
|
if( sqliteExprCheck(pParse, pHaving, 1, &isAgg) ){
|
|
goto select_end;
|
|
}
|
|
}
|
|
if( pOrderBy ){
|
|
for(i=0; i<pOrderBy->nExpr; i++){
|
|
int iCol;
|
|
Expr *pE = pOrderBy->a[i].pExpr;
|
|
if( sqliteExprIsInteger(pE, &iCol) && iCol>0 && iCol<=pEList->nExpr ){
|
|
sqliteExprDelete(pE);
|
|
pE = pOrderBy->a[i].pExpr = sqliteExprDup(pEList->a[iCol-1].pExpr);
|
|
}
|
|
if( sqliteExprResolveIds(pParse, pTabList, pEList, pE) ){
|
|
goto select_end;
|
|
}
|
|
if( sqliteExprCheck(pParse, pE, isAgg, 0) ){
|
|
goto select_end;
|
|
}
|
|
if( sqliteExprIsConstant(pE) ){
|
|
if( sqliteExprIsInteger(pE, &iCol)==0 ){
|
|
sqliteErrorMsg(pParse,
|
|
"ORDER BY terms must not be non-integer constants");
|
|
goto select_end;
|
|
}else if( iCol<=0 || iCol>pEList->nExpr ){
|
|
sqliteErrorMsg(pParse,
|
|
"ORDER BY column number %d out of range - should be "
|
|
"between 1 and %d", iCol, pEList->nExpr);
|
|
goto select_end;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
if( pGroupBy ){
|
|
for(i=0; i<pGroupBy->nExpr; i++){
|
|
int iCol;
|
|
Expr *pE = pGroupBy->a[i].pExpr;
|
|
if( sqliteExprIsInteger(pE, &iCol) && iCol>0 && iCol<=pEList->nExpr ){
|
|
sqliteExprDelete(pE);
|
|
pE = pGroupBy->a[i].pExpr = sqliteExprDup(pEList->a[iCol-1].pExpr);
|
|
}
|
|
if( sqliteExprResolveIds(pParse, pTabList, pEList, pE) ){
|
|
goto select_end;
|
|
}
|
|
if( sqliteExprCheck(pParse, pE, isAgg, 0) ){
|
|
goto select_end;
|
|
}
|
|
if( sqliteExprIsConstant(pE) ){
|
|
if( sqliteExprIsInteger(pE, &iCol)==0 ){
|
|
sqliteErrorMsg(pParse,
|
|
"GROUP BY terms must not be non-integer constants");
|
|
goto select_end;
|
|
}else if( iCol<=0 || iCol>pEList->nExpr ){
|
|
sqliteErrorMsg(pParse,
|
|
"GROUP BY column number %d out of range - should be "
|
|
"between 1 and %d", iCol, pEList->nExpr);
|
|
goto select_end;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Begin generating code.
|
|
*/
|
|
v = sqliteGetVdbe(pParse);
|
|
if( v==0 ) goto select_end;
|
|
|
|
/* Identify column names if we will be using them in a callback. This
|
|
** step is skipped if the output is going to some other destination.
|
|
*/
|
|
if( eDest==SRT_Callback ){
|
|
generateColumnNames(pParse, pTabList, pEList);
|
|
}
|
|
|
|
/* Check for the special case of a min() or max() function by itself
|
|
** in the result set.
|
|
*/
|
|
if( simpleMinMaxQuery(pParse, p, eDest, iParm) ){
|
|
rc = 0;
|
|
goto select_end;
|
|
}
|
|
|
|
/* Generate code for all sub-queries in the FROM clause
|
|
*/
|
|
for(i=0; i<pTabList->nSrc; i++){
|
|
const char *zSavedAuthContext;
|
|
int needRestoreContext;
|
|
|
|
if( pTabList->a[i].pSelect==0 ) continue;
|
|
if( pTabList->a[i].zName!=0 ){
|
|
zSavedAuthContext = pParse->zAuthContext;
|
|
pParse->zAuthContext = pTabList->a[i].zName;
|
|
needRestoreContext = 1;
|
|
}else{
|
|
needRestoreContext = 0;
|
|
}
|
|
sqliteSelect(pParse, pTabList->a[i].pSelect, SRT_TempTable,
|
|
pTabList->a[i].iCursor, p, i, &isAgg);
|
|
if( needRestoreContext ){
|
|
pParse->zAuthContext = zSavedAuthContext;
|
|
}
|
|
pTabList = p->pSrc;
|
|
pWhere = p->pWhere;
|
|
if( eDest!=SRT_Union && eDest!=SRT_Except && eDest!=SRT_Discard ){
|
|
pOrderBy = p->pOrderBy;
|
|
}
|
|
pGroupBy = p->pGroupBy;
|
|
pHaving = p->pHaving;
|
|
isDistinct = p->isDistinct;
|
|
}
|
|
|
|
/* Check to see if this is a subquery that can be "flattened" into its parent.
|
|
** If flattening is a possiblity, do so and return immediately.
|
|
*/
|
|
if( pParent && pParentAgg &&
|
|
flattenSubquery(pParse, pParent, parentTab, *pParentAgg, isAgg) ){
|
|
if( isAgg ) *pParentAgg = 1;
|
|
return rc;
|
|
}
|
|
|
|
/* Set the limiter.
|
|
*/
|
|
computeLimitRegisters(pParse, p);
|
|
|
|
/* Identify column types if we will be using a callback. This
|
|
** step is skipped if the output is going to a destination other
|
|
** than a callback.
|
|
**
|
|
** We have to do this separately from the creation of column names
|
|
** above because if the pTabList contains views then they will not
|
|
** have been resolved and we will not know the column types until
|
|
** now.
|
|
*/
|
|
if( eDest==SRT_Callback ){
|
|
generateColumnTypes(pParse, pTabList, pEList);
|
|
}
|
|
|
|
/* If the output is destined for a temporary table, open that table.
|
|
*/
|
|
if( eDest==SRT_TempTable ){
|
|
sqliteVdbeAddOp(v, OP_OpenTemp, iParm, 0);
|
|
}
|
|
|
|
/* Do an analysis of aggregate expressions.
|
|
*/
|
|
sqliteAggregateInfoReset(pParse);
|
|
if( isAgg || pGroupBy ){
|
|
assert( pParse->nAgg==0 );
|
|
isAgg = 1;
|
|
for(i=0; i<pEList->nExpr; i++){
|
|
if( sqliteExprAnalyzeAggregates(pParse, pEList->a[i].pExpr) ){
|
|
goto select_end;
|
|
}
|
|
}
|
|
if( pGroupBy ){
|
|
for(i=0; i<pGroupBy->nExpr; i++){
|
|
if( sqliteExprAnalyzeAggregates(pParse, pGroupBy->a[i].pExpr) ){
|
|
goto select_end;
|
|
}
|
|
}
|
|
}
|
|
if( pHaving && sqliteExprAnalyzeAggregates(pParse, pHaving) ){
|
|
goto select_end;
|
|
}
|
|
if( pOrderBy ){
|
|
for(i=0; i<pOrderBy->nExpr; i++){
|
|
if( sqliteExprAnalyzeAggregates(pParse, pOrderBy->a[i].pExpr) ){
|
|
goto select_end;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Reset the aggregator
|
|
*/
|
|
if( isAgg ){
|
|
sqliteVdbeAddOp(v, OP_AggReset, 0, pParse->nAgg);
|
|
for(i=0; i<pParse->nAgg; i++){
|
|
FuncDef *pFunc;
|
|
if( (pFunc = pParse->aAgg[i].pFunc)!=0 && pFunc->xFinalize!=0 ){
|
|
sqliteVdbeOp3(v, OP_AggInit, 0, i, (char*)pFunc, P3_POINTER);
|
|
}
|
|
}
|
|
if( pGroupBy==0 ){
|
|
sqliteVdbeAddOp(v, OP_String, 0, 0);
|
|
sqliteVdbeAddOp(v, OP_AggFocus, 0, 0);
|
|
}
|
|
}
|
|
|
|
/* Initialize the memory cell to NULL
|
|
*/
|
|
if( eDest==SRT_Mem ){
|
|
sqliteVdbeAddOp(v, OP_String, 0, 0);
|
|
sqliteVdbeAddOp(v, OP_MemStore, iParm, 1);
|
|
}
|
|
|
|
/* Open a temporary table to use for the distinct set.
|
|
*/
|
|
if( isDistinct ){
|
|
distinct = pParse->nTab++;
|
|
sqliteVdbeAddOp(v, OP_OpenTemp, distinct, 1);
|
|
}else{
|
|
distinct = -1;
|
|
}
|
|
|
|
/* Begin the database scan
|
|
*/
|
|
pWInfo = sqliteWhereBegin(pParse, pTabList, pWhere, 0,
|
|
pGroupBy ? 0 : &pOrderBy);
|
|
if( pWInfo==0 ) goto select_end;
|
|
|
|
/* Use the standard inner loop if we are not dealing with
|
|
** aggregates
|
|
*/
|
|
if( !isAgg ){
|
|
if( selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, distinct, eDest,
|
|
iParm, pWInfo->iContinue, pWInfo->iBreak) ){
|
|
goto select_end;
|
|
}
|
|
}
|
|
|
|
/* If we are dealing with aggregates, then do the special aggregate
|
|
** processing.
|
|
*/
|
|
else{
|
|
AggExpr *pAgg;
|
|
if( pGroupBy ){
|
|
int lbl1;
|
|
for(i=0; i<pGroupBy->nExpr; i++){
|
|
sqliteExprCode(pParse, pGroupBy->a[i].pExpr);
|
|
}
|
|
sqliteVdbeAddOp(v, OP_MakeKey, pGroupBy->nExpr, 0);
|
|
if( pParse->db->file_format>=4 ) sqliteAddKeyType(v, pGroupBy);
|
|
lbl1 = sqliteVdbeMakeLabel(v);
|
|
sqliteVdbeAddOp(v, OP_AggFocus, 0, lbl1);
|
|
for(i=0, pAgg=pParse->aAgg; i<pParse->nAgg; i++, pAgg++){
|
|
if( pAgg->isAgg ) continue;
|
|
sqliteExprCode(pParse, pAgg->pExpr);
|
|
sqliteVdbeAddOp(v, OP_AggSet, 0, i);
|
|
}
|
|
sqliteVdbeResolveLabel(v, lbl1);
|
|
}
|
|
for(i=0, pAgg=pParse->aAgg; i<pParse->nAgg; i++, pAgg++){
|
|
Expr *pE;
|
|
int nExpr;
|
|
FuncDef *pDef;
|
|
if( !pAgg->isAgg ) continue;
|
|
assert( pAgg->pFunc!=0 );
|
|
assert( pAgg->pFunc->xStep!=0 );
|
|
pDef = pAgg->pFunc;
|
|
pE = pAgg->pExpr;
|
|
assert( pE!=0 );
|
|
assert( pE->op==TK_AGG_FUNCTION );
|
|
nExpr = sqliteExprCodeExprList(pParse, pE->pList, pDef->includeTypes);
|
|
sqliteVdbeAddOp(v, OP_Integer, i, 0);
|
|
sqliteVdbeOp3(v, OP_AggFunc, 0, nExpr, (char*)pDef, P3_POINTER);
|
|
}
|
|
}
|
|
|
|
/* End the database scan loop.
|
|
*/
|
|
sqliteWhereEnd(pWInfo);
|
|
|
|
/* If we are processing aggregates, we need to set up a second loop
|
|
** over all of the aggregate values and process them.
|
|
*/
|
|
if( isAgg ){
|
|
int endagg = sqliteVdbeMakeLabel(v);
|
|
int startagg;
|
|
startagg = sqliteVdbeAddOp(v, OP_AggNext, 0, endagg);
|
|
pParse->useAgg = 1;
|
|
if( pHaving ){
|
|
sqliteExprIfFalse(pParse, pHaving, startagg, 1);
|
|
}
|
|
if( selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, distinct, eDest,
|
|
iParm, startagg, endagg) ){
|
|
goto select_end;
|
|
}
|
|
sqliteVdbeAddOp(v, OP_Goto, 0, startagg);
|
|
sqliteVdbeResolveLabel(v, endagg);
|
|
sqliteVdbeAddOp(v, OP_Noop, 0, 0);
|
|
pParse->useAgg = 0;
|
|
}
|
|
|
|
/* If there is an ORDER BY clause, then we need to sort the results
|
|
** and send them to the callback one by one.
|
|
*/
|
|
if( pOrderBy ){
|
|
generateSortTail(p, v, pEList->nExpr, eDest, iParm);
|
|
}
|
|
|
|
/* If this was a subquery, we have now converted the subquery into a
|
|
** temporary table. So delete the subquery structure from the parent
|
|
** to prevent this subquery from being evaluated again and to force the
|
|
** the use of the temporary table.
|
|
*/
|
|
if( pParent ){
|
|
assert( pParent->pSrc->nSrc>parentTab );
|
|
assert( pParent->pSrc->a[parentTab].pSelect==p );
|
|
sqliteSelectDelete(p);
|
|
pParent->pSrc->a[parentTab].pSelect = 0;
|
|
}
|
|
|
|
/* The SELECT was successfully coded. Set the return code to 0
|
|
** to indicate no errors.
|
|
*/
|
|
rc = 0;
|
|
|
|
/* Control jumps to here if an error is encountered above, or upon
|
|
** successful coding of the SELECT.
|
|
*/
|
|
select_end:
|
|
sqliteAggregateInfoReset(pParse);
|
|
return rc;
|
|
}
|