Adding upstream version 13.4.upstream/13.4 upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
author: Daniel Baumann <daniel.baumann@progress-linux.org> 2024-05-04 12:19:15 +0000
committer: Daniel Baumann <daniel.baumann@progress-linux.org> 2024-05-04 12:19:15 +0000
commit: 6eb9c5a5657d1fe77b55cc261450f3538d35a94d (patch)
tree: 657d8194422a5daccecfd42d654b8a245ef7b4c8 /doc/src/sgml/html/sql-delete.html
parent: Initial commit. (diff)
download: postgresql-13-upstream.tar.xz
postgresql-13-upstream.zip
1 files changed, 145 insertions, 0 deletions
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+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>DELETE</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets V1.79.1" /><link rel="prev" href="sql-declare.html" title="DECLARE" /><link rel="next" href="sql-discard.html" title="DISCARD" /></head><body id="docContent" class="container-fluid col-10"><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">DELETE</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="sql-declare.html" title="DECLARE">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="sql-commands.html" title="SQL Commands">Up</a></td><th width="60%" align="center">SQL Commands</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 13.4 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="sql-discard.html" title="DISCARD">Next</a></td></tr></table><hr></hr></div><div class="refentry" id="SQL-DELETE"><div class="titlepage"></div><a id="id-1.9.3.100.1" class="indexterm"></a><div class="refnamediv"><h2><span class="refentrytitle">DELETE</span></h2><p>DELETE — delete rows of a table</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><pre class="synopsis">
+[ WITH [ RECURSIVE ] <em class="replaceable"><code>with_query</code></em> [, ...] ]
+DELETE FROM [ ONLY ] <em class="replaceable"><code>table_name</code></em> [ * ] [ [ AS ] <em class="replaceable"><code>alias</code></em> ]
+    [ USING <em class="replaceable"><code>from_item</code></em> [, ...] ]
+    [ WHERE <em class="replaceable"><code>condition</code></em> | WHERE CURRENT OF <em class="replaceable"><code>cursor_name</code></em> ]
+    [ RETURNING * | <em class="replaceable"><code>output_expression</code></em> [ [ AS ] <em class="replaceable"><code>output_name</code></em> ] [, ...] ]
+</pre></div><div class="refsect1" id="id-1.9.3.100.5"><h2>Description</h2><p>
+   <code class="command">DELETE</code> deletes rows that satisfy the
+   <code class="literal">WHERE</code> clause from the specified table.  If the
+   <code class="literal">WHERE</code> clause is absent, the effect is to delete
+   all rows in the table.  The result is a valid, but empty table.
+  </p><div class="tip"><h3 class="title">Tip</h3><p>
+     <a class="xref" href="sql-truncate.html" title="TRUNCATE"><span class="refentrytitle">TRUNCATE</span></a> provides a
+     faster mechanism to remove all rows from a table.
+    </p></div><p>
+   There are two ways to delete rows in a table using information
+   contained in other tables in the database: using sub-selects, or
+   specifying additional tables in the <code class="literal">USING</code> clause.
+   Which technique is more appropriate depends on the specific
+   circumstances.
+  </p><p>
+   The optional <code class="literal">RETURNING</code> clause causes <code class="command">DELETE</code>
+   to compute and return value(s) based on each row actually deleted.
+   Any expression using the table's columns, and/or columns of other
+   tables mentioned in <code class="literal">USING</code>, can be computed.
+   The syntax of the <code class="literal">RETURNING</code> list is identical to that of the
+   output list of <code class="command">SELECT</code>.
+  </p><p>
+   You must have the <code class="literal">DELETE</code> privilege on the table
+   to delete from it, as well as the <code class="literal">SELECT</code>
+   privilege for any table in the <code class="literal">USING</code> clause or
+   whose values are read in the <em class="replaceable"><code>condition</code></em>.
+  </p></div><div class="refsect1" id="id-1.9.3.100.6"><h2>Parameters</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="replaceable"><code>with_query</code></em></span></dt><dd><p>
+      The <code class="literal">WITH</code> clause allows you to specify one or more
+      subqueries that can be referenced by name in the <code class="command">DELETE</code>
+      query. See <a class="xref" href="queries-with.html" title="7.8. WITH Queries (Common Table Expressions)">Section 7.8</a> and <a class="xref" href="sql-select.html" title="SELECT"><span class="refentrytitle">SELECT</span></a>
+      for details.
+     </p></dd><dt><span class="term"><em class="replaceable"><code>table_name</code></em></span></dt><dd><p>
+      The name (optionally schema-qualified) of the table to delete rows
+      from.  If <code class="literal">ONLY</code> is specified before the table name,
+      matching rows are deleted from the named table only.  If
+      <code class="literal">ONLY</code> is not specified, matching rows are also deleted
+      from any tables inheriting from the named table.  Optionally,
+      <code class="literal">*</code> can be specified after the table name to explicitly
+      indicate that descendant tables are included.
+     </p></dd><dt><span class="term"><em class="replaceable"><code>alias</code></em></span></dt><dd><p>
+      A substitute name for the target table. When an alias is
+      provided, it completely hides the actual name of the table.  For
+      example, given <code class="literal">DELETE FROM foo AS f</code>, the remainder
+      of the <code class="command">DELETE</code> statement must refer to this
+      table as <code class="literal">f</code> not <code class="literal">foo</code>.
+     </p></dd><dt><span class="term"><em class="replaceable"><code>from_item</code></em></span></dt><dd><p>
+      A table expression allowing columns from other tables to appear
+      in the <code class="literal">WHERE</code> condition.  This uses the same
+      syntax as the <a class="link" href="sql-select.html#SQL-FROM" title="FROM Clause"><code class="literal">FROM</code></a>
+      clause of a <code class="command">SELECT</code> statement; for example, an alias
+      for the table name can be specified.  Do not repeat the target
+      table as a <em class="replaceable"><code>from_item</code></em>
+      unless you wish to set up a self-join (in which case it must appear
+      with an alias in the <em class="replaceable"><code>from_item</code></em>).
+     </p></dd><dt><span class="term"><em class="replaceable"><code>condition</code></em></span></dt><dd><p>
+      An expression that returns a value of type <code class="type">boolean</code>.
+      Only rows for which this expression returns <code class="literal">true</code>
+      will be deleted.
+     </p></dd><dt><span class="term"><em class="replaceable"><code>cursor_name</code></em></span></dt><dd><p>
+      The name of the cursor to use in a <code class="literal">WHERE CURRENT OF</code>
+      condition.  The row to be deleted is the one most recently fetched
+      from this cursor.  The cursor must be a non-grouping
+      query on the <code class="command">DELETE</code>'s target table.
+      Note that <code class="literal">WHERE CURRENT OF</code> cannot be
+      specified together with a Boolean condition.  See
+      <a class="xref" href="sql-declare.html" title="DECLARE"><span class="refentrytitle">DECLARE</span></a>
+      for more information about using cursors with
+      <code class="literal">WHERE CURRENT OF</code>.
+     </p></dd><dt><span class="term"><em class="replaceable"><code>output_expression</code></em></span></dt><dd><p>
+      An expression to be computed and returned by the <code class="command">DELETE</code>
+      command after each row is deleted.  The expression can use any
+      column names of the table named by <em class="replaceable"><code>table_name</code></em>
+      or table(s) listed in <code class="literal">USING</code>.
+      Write <code class="literal">*</code> to return all columns.
+     </p></dd><dt><span class="term"><em class="replaceable"><code>output_name</code></em></span></dt><dd><p>
+      A name to use for a returned column.
+     </p></dd></dl></div></div><div class="refsect1" id="id-1.9.3.100.7"><h2>Outputs</h2><p>
+   On successful completion, a <code class="command">DELETE</code> command returns a command
+   tag of the form
+</p><pre class="screen">
+DELETE <em class="replaceable"><code>count</code></em>
+</pre><p>
+   The <em class="replaceable"><code>count</code></em> is the number
+   of rows deleted.  Note that the number may be less than the number of
+   rows that matched the <em class="replaceable"><code>condition</code></em> when deletes were
+   suppressed by a <code class="literal">BEFORE DELETE</code> trigger.  If <em class="replaceable"><code>count</code></em> is 0, no rows were deleted by
+   the query (this is not considered an error).
+  </p><p>
+   If the <code class="command">DELETE</code> command contains a <code class="literal">RETURNING</code>
+   clause, the result will be similar to that of a <code class="command">SELECT</code>
+   statement containing the columns and values defined in the
+   <code class="literal">RETURNING</code> list, computed over the row(s) deleted by the
+   command.
+  </p></div><div class="refsect1" id="id-1.9.3.100.8"><h2>Notes</h2><p>
+   <span class="productname">PostgreSQL</span> lets you reference columns of
+   other tables in the <code class="literal">WHERE</code> condition by specifying the
+   other tables in the <code class="literal">USING</code> clause.  For example,
+   to delete all films produced by a given producer, one can do:
+</p><pre class="programlisting">
+DELETE FROM films USING producers
+  WHERE producer_id = producers.id AND producers.name = 'foo';
+</pre><p>
+   What is essentially happening here is a join between <code class="structname">films</code>
+   and <code class="structname">producers</code>, with all successfully joined
+   <code class="structname">films</code> rows being marked for deletion.
+   This syntax is not standard.  A more standard way to do it is:
+</p><pre class="programlisting">
+DELETE FROM films
+  WHERE producer_id IN (SELECT id FROM producers WHERE name = 'foo');
+</pre><p>
+   In some cases the join style is easier to write or faster to
+   execute than the sub-select style.
+  </p></div><div class="refsect1" id="id-1.9.3.100.9"><h2>Examples</h2><p>
+   Delete all films but musicals:
+</p><pre class="programlisting">
+DELETE FROM films WHERE kind &lt;&gt; 'Musical';
+</pre><p>
+  </p><p>
+   Clear the table <code class="literal">films</code>:
+</p><pre class="programlisting">
+DELETE FROM films;
+</pre><p>
+  </p><p>
+   Delete completed tasks, returning full details of the deleted rows:
+</p><pre class="programlisting">
+DELETE FROM tasks WHERE status = 'DONE' RETURNING *;
+</pre><p>
+  </p><p>
+   Delete the row of <code class="structname">tasks</code> on which the cursor
+   <code class="literal">c_tasks</code> is currently positioned:
+</p><pre class="programlisting">
+DELETE FROM tasks WHERE CURRENT OF c_tasks;
+</pre></div><div class="refsect1" id="id-1.9.3.100.10"><h2>Compatibility</h2><p>
+   This command conforms to the <acronym class="acronym">SQL</acronym> standard, except
+   that the <code class="literal">USING</code> and <code class="literal">RETURNING</code> clauses
+   are <span class="productname">PostgreSQL</span> extensions, as is the ability
+   to use <code class="literal">WITH</code> with <code class="command">DELETE</code>.
+  </p></div><div class="refsect1" id="id-1.9.3.100.11"><h2>See Also</h2><span class="simplelist"><a class="xref" href="sql-truncate.html" title="TRUNCATE"><span class="refentrytitle">TRUNCATE</span></a></span></div></div><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navfooter"><hr></hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="sql-declare.html" title="DECLARE">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="sql-commands.html" title="SQL Commands">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="sql-discard.html" title="DISCARD">Next</a></td></tr><tr><td width="40%" align="left" valign="top">DECLARE </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 13.4 Documentation">Home</a></td><td width="40%" align="right" valign="top"> DISCARD</td></tr></table></div></body></html>
+\ No newline at end of file
author	Daniel Baumann <daniel.baumann@progress-linux.org>	2024-05-04 12:19:15 +0000
committer	Daniel Baumann <daniel.baumann@progress-linux.org>	2024-05-04 12:19:15 +0000
commit	6eb9c5a5657d1fe77b55cc261450f3538d35a94d (patch)
tree	657d8194422a5daccecfd42d654b8a245ef7b4c8 /doc/src/sgml/html/sql-delete.html
parent	Initial commit. (diff)
download	postgresql-13-upstream.tar.xz postgresql-13-upstream.zip