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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html><head><title>SQLite Query Language: UPDATE</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="lang.html"><h2>SQL As Understood By SQLite</h2></a><h3>UPDATE</h3><h4><a href="syntaxdiagrams.html#update-stmt">update-stmt:</a></h4><blockquote> <img src="images/syntax/update-stmt.gif"></img> </blockquote><h4><a href="syntaxdiagrams.html#qualified-table-name">qualified-table-name:</a></h4><blockquote> <img src="images/syntax/qualified-table-name.gif"></img> </blockquote><p>The UPDATE statement is used to change the value of columns in selected rows of a table. Each assignment in an UPDATE specifiesa column name to the left of the equals sign and an arbitrary expressionto the right. The expressions may use the values of other columns.All expressions are evaluated before any assignments are made.A WHERE clause can be used to restrict which rows are updated.</p><p>The optional conflict-clause allows the specification of an alternativeconstraint conflict resolution algorithm to use during this one command.See the section titled<a href="lang_conflict.html">ON CONFLICT</a> for additional information.</p><p>If SQLite is built with the <a href="compile.html#enable_update_delete_limit">SQLITE_ENABLE_UPDATE_DELETE_LIMIT</a>compile-time option then the syntax of the UPDATE statement is extendedwith optional ORDER BY and LIMIT clauses as follows:</p><h4><a href="syntaxdiagrams.html#update-stmt-limited">update-stmt-limited:</a></h4><blockquote> <img src="images/syntax/update-stmt-limited.gif"></img> </blockquote><p>The optional LIMIT clause can be used to limit the number ofrows modifed, and thereby limit the size of the transaction.The ORDER BY clause is used only to determine which rows fallwithin the LIMIT. The order in which rows are modified is arbitraryand is not determined by the ORDER BY clause.</p><hr><small><i>This page last modified 2008/11/12 14:57:19 UTC</i></small></div></body></html>⌨️ 快捷键说明
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