183 lines
6.9 KiB
HTML
183 lines
6.9 KiB
HTML
<!DOCTYPE html>
|
|
<html><head>
|
|
<meta name="viewport" content="width=device-width, initial-scale=1.0">
|
|
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
|
|
<link href="../sqlite.css" rel="stylesheet">
|
|
<title>Convenience Routines For Running Queries</title>
|
|
<!-- path=../ -->
|
|
</head>
|
|
<body>
|
|
<div class=nosearch>
|
|
<a href="../index.html">
|
|
<img class="logo" src="../images/sqlite370_banner.gif" alt="SQLite" border="0">
|
|
</a>
|
|
<div><!-- IE hack to prevent disappearing logo --></div>
|
|
<div class="tagline desktoponly">
|
|
Small. Fast. Reliable.<br>Choose any three.
|
|
</div>
|
|
<div class="menu mainmenu">
|
|
<ul>
|
|
<li><a href="../index.html">Home</a>
|
|
<li class='mobileonly'><a href="javascript:void(0)" onclick='toggle_div("submenu")'>Menu</a>
|
|
<li class='wideonly'><a href='../about.html'>About</a>
|
|
<li class='desktoponly'><a href="../docs.html">Documentation</a>
|
|
<li class='desktoponly'><a href="../download.html">Download</a>
|
|
<li class='wideonly'><a href='../copyright.html'>License</a>
|
|
<li class='desktoponly'><a href="../support.html">Support</a>
|
|
<li class='desktoponly'><a href="../prosupport.html">Purchase</a>
|
|
<li class='search' id='search_menubutton'>
|
|
<a href="javascript:void(0)" onclick='toggle_search()'>Search</a>
|
|
</ul>
|
|
</div>
|
|
<div class="menu submenu" id="submenu">
|
|
<ul>
|
|
<li><a href='../about.html'>About</a>
|
|
<li><a href='../docs.html'>Documentation</a>
|
|
<li><a href='../download.html'>Download</a>
|
|
<li><a href='../support.html'>Support</a>
|
|
<li><a href='../prosupport.html'>Purchase</a>
|
|
</ul>
|
|
</div>
|
|
<div class="searchmenu" id="searchmenu">
|
|
<form method="GET" action="../search">
|
|
<select name="s" id="searchtype">
|
|
<option value="d">Search Documentation</option>
|
|
<option value="c">Search Changelog</option>
|
|
</select>
|
|
<input type="text" name="q" id="searchbox" value="">
|
|
<input type="submit" value="Go">
|
|
</form>
|
|
</div>
|
|
</div>
|
|
<script>
|
|
function toggle_div(nm) {
|
|
var w = document.getElementById(nm);
|
|
if( w.style.display=="block" ){
|
|
w.style.display = "none";
|
|
}else{
|
|
w.style.display = "block";
|
|
}
|
|
}
|
|
function toggle_search() {
|
|
var w = document.getElementById("searchmenu");
|
|
if( w.style.display=="block" ){
|
|
w.style.display = "none";
|
|
} else {
|
|
w.style.display = "block";
|
|
setTimeout(function(){
|
|
document.getElementById("searchbox").focus()
|
|
}, 30);
|
|
}
|
|
}
|
|
function div_off(nm){document.getElementById(nm).style.display="none";}
|
|
window.onbeforeunload = function(e){div_off("submenu");}
|
|
/* Disable the Search feature if we are not operating from CGI, since */
|
|
/* Search is accomplished using CGI and will not work without it. */
|
|
if( !location.origin || !location.origin.match || !location.origin.match(/http/) ){
|
|
document.getElementById("search_menubutton").style.display = "none";
|
|
}
|
|
/* Used by the Hide/Show button beside syntax diagrams, to toggle the */
|
|
function hideorshow(btn,obj){
|
|
var x = document.getElementById(obj);
|
|
var b = document.getElementById(btn);
|
|
if( x.style.display!='none' ){
|
|
x.style.display = 'none';
|
|
b.innerHTML='show';
|
|
}else{
|
|
x.style.display = '';
|
|
b.innerHTML='hide';
|
|
}
|
|
return false;
|
|
}
|
|
</script>
|
|
</div>
|
|
<!-- keywords: sqlite3_free_table sqlite3_get_table -->
|
|
<div class=nosearch>
|
|
<a href="intro.html"><h2>SQLite C Interface</h2></a>
|
|
<h2>Convenience Routines For Running Queries</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_get_table(
|
|
sqlite3 *db, /* An open database */
|
|
const char *zSql, /* SQL to be evaluated */
|
|
char ***pazResult, /* Results of the query */
|
|
int *pnRow, /* Number of result rows written here */
|
|
int *pnColumn, /* Number of result columns written here */
|
|
char **pzErrmsg /* Error msg written here */
|
|
);
|
|
void sqlite3_free_table(char **result);
|
|
</pre></blockquote>
|
|
<p>
|
|
This is a legacy interface that is preserved for backwards compatibility.
|
|
Use of this interface is not recommended.</p>
|
|
|
|
<p>Definition: A <b>result table</b> is memory data structure created by the
|
|
<a href="../c3ref/free_table.html">sqlite3_get_table()</a> interface. A result table records the
|
|
complete query results from one or more queries.</p>
|
|
|
|
<p>The table conceptually has a number of rows and columns. But
|
|
these numbers are not part of the result table itself. These
|
|
numbers are obtained separately. Let N be the number of rows
|
|
and M be the number of columns.</p>
|
|
|
|
<p>A result table is an array of pointers to zero-terminated UTF-8 strings.
|
|
There are (N+1)*M elements in the array. The first M pointers point
|
|
to zero-terminated strings that contain the names of the columns.
|
|
The remaining entries all point to query results. NULL values result
|
|
in NULL pointers. All other values are in their UTF-8 zero-terminated
|
|
string representation as returned by <a href="../c3ref/column_blob.html">sqlite3_column_text()</a>.</p>
|
|
|
|
<p>A result table might consist of one or more memory allocations.
|
|
It is not safe to pass a result table directly to <a href="../c3ref/free.html">sqlite3_free()</a>.
|
|
A result table should be deallocated using <a href="../c3ref/free_table.html">sqlite3_free_table()</a>.</p>
|
|
|
|
<p>As an example of the result table format, suppose a query result
|
|
is as follows:</p>
|
|
|
|
<p><blockquote><pre>
|
|
Name | Age
|
|
-----------------------
|
|
Alice | 43
|
|
Bob | 28
|
|
Cindy | 21
|
|
</pre></blockquote></p>
|
|
|
|
<p>There are two columns (M==2) and three rows (N==3). Thus the
|
|
result table has 8 entries. Suppose the result table is stored
|
|
in an array named azResult. Then azResult holds this content:</p>
|
|
|
|
<p><blockquote><pre>
|
|
azResult[0] = "Name";
|
|
azResult[1] = "Age";
|
|
azResult[2] = "Alice";
|
|
azResult[3] = "43";
|
|
azResult[4] = "Bob";
|
|
azResult[5] = "28";
|
|
azResult[6] = "Cindy";
|
|
azResult[7] = "21";
|
|
</pre></blockquote></p>
|
|
|
|
<p>The sqlite3_get_table() function evaluates one or more
|
|
semicolon-separated SQL statements in the zero-terminated UTF-8
|
|
string of its 2nd parameter and returns a result table to the
|
|
pointer given in its 3rd parameter.</p>
|
|
|
|
<p>After the application has finished with the result from sqlite3_get_table(),
|
|
it must pass the result table pointer to sqlite3_free_table() in order to
|
|
release the memory that was malloced. Because of the way the
|
|
<a href="../c3ref/free.html">sqlite3_malloc()</a> happens within sqlite3_get_table(), the calling
|
|
function must not try to call <a href="../c3ref/free.html">sqlite3_free()</a> directly. Only
|
|
<a href="../c3ref/free_table.html">sqlite3_free_table()</a> is able to release the memory properly and safely.</p>
|
|
|
|
<p>The sqlite3_get_table() interface is implemented as a wrapper around
|
|
<a href="../c3ref/exec.html">sqlite3_exec()</a>. The sqlite3_get_table() routine does not have access
|
|
to any internal data structures of SQLite. It uses only the public
|
|
interface defined here. As a consequence, errors that occur in the
|
|
wrapper layer outside of the internal <a href="../c3ref/exec.html">sqlite3_exec()</a> call are not
|
|
reflected in subsequent calls to <a href="../c3ref/errcode.html">sqlite3_errcode()</a> or
|
|
<a href="../c3ref/errcode.html">sqlite3_errmsg()</a>.
|
|
</p><p>See also lists of
|
|
<a href="objlist.html">Objects</a>,
|
|
<a href="constlist.html">Constants</a>, and
|
|
<a href="funclist.html">Functions</a>.</p>
|