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192 lines
4.5 KiB
Plaintext
192 lines
4.5 KiB
Plaintext
<REFENTRY ID="SQL-DELETE">
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<REFMETA>
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<REFENTRYTITLE>
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DELETE
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</REFENTRYTITLE>
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<REFMISCINFO>SQL - Language Statements</REFMISCINFO>
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</REFMETA>
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<REFNAMEDIV>
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<REFNAME>
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DELETE
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</REFNAME>
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<REFPURPOSE>
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Deletes rows from a table
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</REFPURPOSE>
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</refnamediv>
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<REFSYNOPSISDIV>
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<REFSYNOPSISDIVINFO>
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<DATE>1998-04-15</DATE>
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</REFSYNOPSISDIVINFO>
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<SYNOPSIS>
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DELETE FROM <REPLACEABLE CLASS="PARAMETER">table</REPLACEABLE> [ WHERE <REPLACEABLE CLASS="PARAMETER">condition</REPLACEABLE> ]
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</SYNOPSIS>
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<REFSECT2 ID="R2-SQL-DELETE-1">
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<REFSECT2INFO>
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<DATE>1998-04-15</DATE>
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</REFSECT2INFO>
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<TITLE>
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Inputs
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</TITLE>
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<PARA>
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</PARA>
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<VARIABLELIST>
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<VARLISTENTRY>
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<TERM>
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<replaceable class="parameter">table</replaceable>
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</TERM>
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<LISTITEM>
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<PARA>
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The name of an existing table.
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</PARA>
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</LISTITEM>
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</VARLISTENTRY>
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<VARLISTENTRY>
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<TERM>
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<replaceable class="parameter">condition</replaceable>
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</TERM>
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<LISTITEM>
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<PARA>
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This is an SQL selection query which returns the rows which
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are to be deleted.
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</PARA>
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<PARA>
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Refer to the SELECT statement for further description
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of the WHERE clause.
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</PARA>
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</LISTITEM>
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</VARLISTENTRY>
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</variablelist>
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</REFSECT2>
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<REFSECT2 ID="R2-SQL-DELETE-2">
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<REFSECT2INFO>
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<DATE>1998-04-15</DATE>
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</REFSECT2INFO>
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<TITLE>
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Outputs
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</TITLE>
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<PARA>
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<VARIABLELIST>
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<VARLISTENTRY>
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<TERM>
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<ReturnValue> DELETE <replaceable class="parameter">count</replaceable></ReturnValue>
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</TERM>
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<LISTITEM>
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<PARA>
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Message returned if items are successfully deleted. The
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<replaceable class="parameter">count</replaceable> is the number
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of rows deleted.
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</PARA>
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<PARA>
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If <replaceable class="parameter">count</replaceable> is 0,
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no rows were deleted.
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</para>
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</listitem>
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</varlistentry>
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</VARIABLELIST>
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</para>
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</REFSECT2>
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</REFSYNOPSISDIV>
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<REFSECT1 ID="R1-SQL-DELETE-1">
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<REFSECT1INFO>
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<DATE>1998-04-15</DATE>
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</REFSECT1INFO>
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<TITLE>
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Description
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</TITLE>
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<PARA>
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DELETE removes rows which satisfy the WHERE <replaceable class="parameter">condition</replaceable>,
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from the specified table.
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</PARA>
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<PARA>
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If the <replaceable class="parameter">condition</replaceable> is absent,
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the effect is to delete all rows in the table.
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The result is a valid, but empty table.
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</PARA>
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<PARA>
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You must have write access to the table in order to modify
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it, as well as read access to any table whose values are
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read in the <replaceable class="parameter">condition</replaceable>.
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</PARA>
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</REFSECT1>
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<REFSECT1 ID="R1-SQL-DELETE-2">
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<TITLE>
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Usage
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</TITLE>
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<PARA>
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Remove all films but musicals:
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</PARA>
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<ProgramListing>
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DETETE FROM films WHERE kind <> 'Musical';
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SELECT * FROM films;
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code |title |did| date_prod|kind |len
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-----+-------------------------+---+----------+----------+------
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UA501|West Side Story |105|1961-01-03|Musical | 02:32
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TC901|The King and I |109|1956-08-11|Musical | 02:13
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WD101|Bed Knobs and Broomsticks|111| |Musical | 01:57
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(3 rows)
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</ProgramListing>
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<para>
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Clear the table <literal>films</literal>:
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</para>
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<programlisting>
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DELETE FROM films;
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SELECT * FROM films;
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code|title|did|date_prod|kind|len
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----+-----+---+---------+----+---
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(0 rows)
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</programlisting>
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</REFSECT1>
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<REFSECT1 ID="R1-SQL-DELETE-3">
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<TITLE>
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Compatibility
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</TITLE>
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<PARA>
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</PARA>
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<REFSECT2 ID="R2-SQL-DELETE-4">
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<REFSECT2INFO>
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<DATE>1998-04-15</DATE>
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</REFSECT2INFO>
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<TITLE>
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SQL92
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</TITLE>
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<PARA>
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<acronym>SQL92</acronym> allows a positioned DELETE statement:
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</PARA>
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<synopsis>
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DELETE FROM <replaceable class="parameter">table</replaceable> WHERE CURRENT OF <replaceable class="parameter">cursor</replaceable>
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</synopsis>
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<para>
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where <replaceable class="parameter">cursor</replaceable> identifies an open cursor. Interactive cursors in <productname>Postgres</productname> are read-only.
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</para>
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</refsect2>
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</refsect1>
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</REFENTRY>
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<!-- Keep this comment at the end of the file
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Local variables:
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mode: sgml
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sgml-omittag:t
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sgml-shorttag:t
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sgml-minimize-attributes:nil
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sgml-always-quote-attributes:t
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sgml-indent-step:1
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sgml-indent-data:t
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sgml-parent-document:nil
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sgml-default-dtd-file:"../reference.ced"
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sgml-exposed-tags:nil
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sgml-local-catalogs:"/usr/lib/sgml/catalog"
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sgml-local-ecat-files:nil
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End:
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-->
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