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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: DELETE</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>DELETE</h3><table cellpadding="10"><tr><td align="right" valign="top"><i><font color="#ff3434">sql-statement</font></i> ::=</td><td><b><font color="#2c2cf0">DELETE FROM </font></b>[<b><font color="#2c2cf0"></font></b><i><font color="#ff3434">database-name</font></i><b><font color="#2c2cf0"> <big>.</big></font></b>]<b><font color="#2c2cf0"> </font></b><i><font color="#ff3434">table-name</font></i><b><font color="#2c2cf0"> </font></b>[<b><font color="#2c2cf0">WHERE </font></b><i><font color="#ff3434">expr</font></i><b><font color="#2c2cf0"></font></b>]<b><font color="#2c2cf0"></font></b></td></tr></table><p>The DELETE command is used to remove records from a table.The command consists of the "DELETE FROM" keywords followed bythe name of the table from which records are to be removed.</p><p>Without a WHERE clause, all rows of the table are removed.If a WHERE clause is supplied, then only those rows that matchthe expression are removed.</p><p>When the WHERE clause is omitted from a DELETE statement,SQLite uses an optimization to erase the entire table contentwithout having to visit each row of the table individual.This "truncate" optimization makes the delete run much faster.However, it also means that the <a href="c3ref/changes.html">sqlite3_changes()</a> interfaceand the <a href="pragma.html#pragma_count_changes">count_changes</a> PRAGMAwill not actually return the number of deleted rows. If youneed to delete every row of a table and still have<a href="c3ref/changes.html">sqlite3_changes()</a> and <a href="pragma.html#pragma_count_changes">count_changes</a> work correctly, thenuse WHERE clause that is always true:</p><blockquote><pre>DELETE FROM sometable WHERE 1;</pre></blockquote><hr><small><i>This page last modified 2008/04/27 17:48:52 UTC</i></small></div></body></html>⌨️ 快捷键说明
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