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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html><head><title>Column Names In A Result Set</title><style type="text/css">body { margin: auto; font-family: "Verdana" "sans-serif"; padding: 8px 1%;}a { color: #45735f }a:visited { color: #734559 }.logo { position:absolute; margin:3px; }.tagline { float:right; text-align:right; font-style:italic; width:240px; margin:12px; margin-top:58px;}.toolbar { font-variant: small-caps; text-align: center; line-height: 1.6em; margin: 0; padding:1px 8px;}.toolbar a { color: white; text-decoration: none; padding: 6px 12px; }.toolbar a:visited { color: white; }.toolbar a:hover { color: #80a796; background: white; }.content { margin: 5%; }.content dt { font-weight:bold; }.content dd { margin-bottom: 25px; margin-left:20%; }.content ul { padding:0px; padding-left: 15px; margin:0px; }/* rounded corners */.se { background: url(../images/se.png) 100% 100% no-repeat #80a796}.sw { background: url(../images/sw.png) 0% 100% no-repeat }.ne { background: url(../images/ne.png) 100% 0% no-repeat }.nw { background: url(../images/nw.png) 0% 0% no-repeat }</style><meta http-equiv="content-type" content="text/html; charset=UTF-8"> </head><body><div><!-- container div to satisfy validator --><a href="../index.html"><img class="logo" src="../images/SQLite.gif" alt="SQLite Logo" border="0"></a><div><!-- IE hack to prevent disappearing logo--></div><div class="tagline">Small. Fast. Reliable.<br>Choose any three.</div><table width=100% style="clear:both"><tr><td> <div class="se"><div class="sw"><div class="ne"><div class="nw"> <div class="toolbar"> <a href="../about.html">About</a> <a href="../sitemap.html">Sitemap</a> <a href="../docs.html">Documentation</a> <a href="../download.html">Download</a> <a href="../copyright.html">License</a> <a href="../news.html">News</a> <a href="http://www.sqlite.org/cvstrac/index">Developers</a> <a href="../support.html">Support</a> </div></div></div></div></div></td></tr></table> <a href="intro.html"><h2>SQLite C Interface</h2></a><h2>Column Names In A Result Set</h2><blockquote><pre>const char *sqlite3_column_name(sqlite3_stmt*, int N);const void *sqlite3_column_name16(sqlite3_stmt*, int N);</pre></blockquote><p>These routines return the name assigned to a particular columnin the result set of a <a href="../lang_select.html">SELECT</a> statement. The sqlite3_column_name()interface returns a pointer to a zero-terminated UTF-8 stringand sqlite3_column_name16() returns a pointer to a zero-terminatedUTF-16 string. The first parameter is the <a href="../c3ref/stmt.html">prepared statement</a>that implements the <a href="../lang_select.html">SELECT</a> statement. The second parameter is thecolumn number. The leftmost column is number 0.</p><p>The returned string pointer is valid until either the <a href="../c3ref/stmt.html">prepared statement</a>is destroyed by <a href="../c3ref/finalize.html">sqlite3_finalize()</a> or until the next call tosqlite3_column_name() or sqlite3_column_name16() on the same column.</p><p>If sqlite3_malloc() fails during the processing of either routine(for example during a conversion from UTF-8 to UTF-16) then aNULL pointer is returned.</p><p>The name of a result column is the value of the "AS" clause forthat column, if there is an AS clause. If there is no AS clausethen the name of the column is unspecified and may change fromone release of SQLite to the next.</p><p><h3>Invariants:</h3><table border="0" cellpadding="5" cellspacing="0"><tr><td valign="top">H13721</td> <td valign="top">A successful invocation of the <a href="../c3ref/column_name.html">sqlite3_column_name(S,N)</a>interface returns the name of the Nth column (where 0 isthe leftmost column) for the result set of the<a href="../c3ref/stmt.html">prepared statement</a> S as a zero-terminated UTF-8 string.</td></tr><tr><td valign="top">H13723</td> <td valign="top">A successful invocation of the <a href="../c3ref/column_name.html">sqlite3_column_name16(S,N)</a>interface returns the name of the Nth column (where 0 isthe leftmost column) for the result set of the<a href="../c3ref/stmt.html">prepared statement</a> S as a zero-terminated UTF-16 stringin the native byte order.</td></tr><tr><td valign="top">H13724</td> <td valign="top">The <a href="../c3ref/column_name.html">sqlite3_column_name()</a> and <a href="../c3ref/column_name.html">sqlite3_column_name16()</a>interfaces return a NULL pointer if they are unable toallocate memory to hold their normal return strings.</td></tr><tr><td valign="top">H13725</td> <td valign="top">If the N parameter to <a href="../c3ref/column_name.html">sqlite3_column_name(S,N)</a> or<a href="../c3ref/column_name.html">sqlite3_column_name16(S,N)</a> is out of range, then theinterfaces return a NULL pointer.</td></tr><tr><td valign="top">H13726</td> <td valign="top">The strings returned by <a href="../c3ref/column_name.html">sqlite3_column_name(S,N)</a> and<a href="../c3ref/column_name.html">sqlite3_column_name16(S,N)</a> are valid until the nextcall to either routine with the same S and N parametersor until <a href="../c3ref/finalize.html">sqlite3_finalize(S)</a> is called.</td></tr><tr><td valign="top">H13727</td> <td valign="top">When a result column of a <a href="../lang_select.html">SELECT</a> statement containsan AS clause, the name of that column is the identifierto the right of the AS keyword.</td></tr></table></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><hr><small><i>This page last modified 2008/12/09 18:44:04 UTC</i></small></div></body></html>⌨️ 快捷键说明
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