granicus.if.org Git - postgresql/blob - doc/src/sgml/ref/delete.sgml

   1 <REFENTRY ID="SQL-DELETE">
   2  <REFMETA>
   3   <REFENTRYTITLE>
   4    DELETE
   5   </REFENTRYTITLE>
   6   <REFMISCINFO>SQL - Language Statements</REFMISCINFO>
   7  </REFMETA>
   8  <REFNAMEDIV>
   9   <REFNAME>
  10    DELETE
  11   </REFNAME>
  12   <REFPURPOSE>
  13    Deletes rows from a table
  14   </REFPURPOSE>
  15
  16
  17  <REFSYNOPSISDIV>
  18   <REFSYNOPSISDIVINFO>
  19    <DATE>1998-04-15</DATE>
  20   </REFSYNOPSISDIVINFO>
  21   <SYNOPSIS>
  22    DELETE FROM <REPLACEABLE CLASS="PARAMETER">table</REPLACEABLE> [ WHERE <REPLACEABLE CLASS="PARAMETER">condition</REPLACEABLE> ]
  23   </SYNOPSIS>
  24
  25   <REFSECT2 ID="R2-SQL-DELETE-1">
  26    <REFSECT2INFO>
  27     <DATE>1998-04-15</DATE>
  28    </REFSECT2INFO>
  29    <TITLE>
  30     Inputs
  31    </TITLE>
  32    <PARA>
  33    </PARA>
  34    <VARIABLELIST>
  35     <VARLISTENTRY>
  36      <TERM>
  37      </TERM>
  38      <LISTITEM>
  39       <PARA>
  40        <VARIABLELIST>
  41         <VARLISTENTRY>
  42          <TERM>
  43           <ReturnValue><replaceable class="parameter">table</replaceable></ReturnValue>
  44          </TERM>
  45          <LISTITEM>
  46           <PARA>
  47           The name of an existing table.
  48           </PARA>
  49          </LISTITEM>
  50         </VARLISTENTRY>
  51         <VARLISTENTRY>
  52          <TERM>
  53           <ReturnValue><replaceable class="parameter">condition</replaceable></ReturnValue>
  54          </TERM>
  55          <LISTITEM>
  56           <PARA>
  57            This is an SQL selection query which returns the rows which
  58            are to be deleted.
  59           </PARA>
  60           <PARA>
  61           Refer to the SELECT statement for further description
  62           of the WHERE clause.
  63           </PARA>
  64          </LISTITEM>
  65         </VARLISTENTRY>
  66        </variablelist>
  67      </LISTITEM>
  68     </VARLISTENTRY>
  69    </VARIABLELIST>
  70   </REFSECT2>
  71
  72   <REFSECT2 ID="R2-SQL-DELETE-2">
  73    <REFSECT2INFO>
  74     <DATE>1998-04-15</DATE>
  75    </REFSECT2INFO>
  76    <TITLE>
  77     Outputs
  78    </TITLE>
  79    <PARA>
  80    </PARA>
  81    <VARIABLELIST>
  82     <VARLISTENTRY>
  83      <TERM>
  84      </TERM>
  85      <LISTITEM>
  86       <PARA>
  87        <VARIABLELIST>
  88         <VARLISTENTRY>
  89          <TERM>
  90           <ReturnValue> DELETE <replaceable class="parameter">count</replaceable></ReturnValue>
  91          </TERM>
  92          <LISTITEM>
  93           <PARA>
  94            Message returned if items are successfully deleted. The
  95            <replaceable class="parameter">count</replaceable> is the number
  96            of rows deleted.
  97           </PARA>
  98           <PARA>
  99            If <replaceable class="parameter">count</replaceable> is 0,
 100            no rows are deleted.
 101           </PARA>
 102          </LISTITEM>
 103         </VARLISTENTRY>
 104        </variablelist>
 105      </LISTITEM>
 106     </VARLISTENTRY>
 107    </VARIABLELIST>
 108   </REFSECT2>
 109 </REFSYNOPSISDIV>
 110
 111  <REFSECT1 ID="R1-SQL-DELETE-1">
 112   <REFSECT1INFO>
 113    <DATE>1998-04-15</DATE>
 114   </REFSECT1INFO>
 115   <TITLE>
 116    Description
 117   </TITLE>
 118   <PARA>
 119    DELETE removes rows which satisfy the WHERE <replaceable class="parameter">condition</replaceable>,
 120    from the specified table.
 121   </PARA>
 122   <PARA>
 123    If the <replaceable class="parameter">condition</replaceable> is absent,
 124    the effect is to delete all rows in the table.
 125    The result is a valid, but empty table.
 126   </PARA>
 127   <PARA>
 128    You must have write access to the table in order to modify
 129    it, as well as read access to any table whose values are
 130    read in the <replaceable class="parameter">condition</replaceable>.
 131   </PARA>
 132  </REFSECT1>
 133
 134  <REFSECT1 ID="R1-SQL-DELETE-2">
 135   <TITLE>
 136    Usage
 137   </TITLE>
 138   <PARA>
 139    Remove all films but musicals:
 140   </PARA>
 141   <ProgramListing>
 142    DELETE FROM films WHERE kind &lt;&gt; 'Musical';
 143
 144    SELECT * FROM films;
 145
 146    code |title                    |did| date_prod|kind      |len
 147    -----+-------------------------+---+----------+----------+------
 148    UA501|West Side Story          |105|1961-01-03|Musical   | 02:32
 149    TC901|The King and I           |109|1956-08-11|Musical   | 02:13
 150    WD101|Bed Knobs and Broomsticks|111|          |Musical   | 01:57
 151   </ProgramListing>
 152   <para>
 153    Clear the table films:
 154   </para>
 155   <programlisting>
 156    DELETE FROM films;
 157
 158    SELECT * FROM films;
 159    code|title|did|date_prod|kind|len
 160    ----+-----+---+---------+----+---
 161    (0 rows)
 162   </programlisting>
 163  </REFSECT1>
 164
 165  <REFSECT1 ID="R1-SQL-DELETE-3">
 166   <TITLE>
 167    Compatibility
 168   </TITLE>
 169   <PARA>
 170   </PARA>
 171
 172   <REFSECT2 ID="R2-SQL-DELETE-4">
 173    <REFSECT2INFO>
 174     <DATE>1998-04-15</DATE>
 175    </REFSECT2INFO>
 176    <TITLE>
 177     SQL92
 178    </TITLE>
 179    <PARA>
 180    SQL92 defines a different syntax for a positioned DELETE statement:
 181    </PARA>
 182
 183    <synopsis>
 184     DELETE FROM <replaceable class="parameter">table</replaceable> WHERE CURRENT OF <replaceable class="parameter">cursor</replaceable>
 185    </synopsis>
 186    <para>
 187    where <replaceable class="parameter">cursor</replaceable> identifies an open cursor.</para>
 188   </refsect2>
 189  </refsect1>
 190 </REFENTRY>
 191
 192 <!-- Keep this comment at the end of the file
 193 Local variables:
 194 mode: sgml
 195 sgml-omittag:t
 196 sgml-shorttag:t
 197 sgml-minimize-attributes:nil
 198 sgml-always-quote-attributes:t
 199 sgml-indent-step:1
 200 sgml-indent-data:t
 201 sgml-parent-document:nil
 202 sgml-default-dtd-file:"../reference.ced"
 203 sgml-exposed-tags:nil
 204 sgml-local-catalogs:"/usr/lib/sgml/catalog"
 205 sgml-local-ecat-files:nil
 206 End:
 207 -->