<REFENTRY ID="SQL-UPDATE">
<REFMETA>
<REFENTRYTITLE>
UPDATE
</REFENTRYTITLE>
<REFMISCINFO>SQL - Language Statements</REFMISCINFO>
</REFMETA>
<REFNAMEDIV>
<REFNAME>
UPDATE
</REFNAME>
<REFPURPOSE>
Replaces values of columns in a table
</REFPURPOSE>

<REFSYNOPSISDIV>
<REFSYNOPSISDIVINFO>
<DATE>1998-09-24</DATE>
</REFSYNOPSISDIVINFO>
<SYNOPSIS>
UPDATE <REPLACEABLE CLASS="PARAMETER">table</replaceable> SET <REPLACEABLE CLASS="PARAMETER">column</replaceable> = <REPLACEABLE CLASS="PARAMETER">expression</replaceable> [, ...]
    [ FROM <REPLACEABLE CLASS="PARAMETER">fromlist</REPLACEABLE> ]
    [ WHERE <REPLACEABLE CLASS="PARAMETER">condition</REPLACEABLE> ]
</SYNOPSIS>

<REFSECT2 ID="R2-SQL-UPDATE-1">
<REFSECT2INFO>
<DATE>1998-09-24</DATE>
</REFSECT2INFO>
<TITLE>
Inputs
</TITLE>
<PARA>

<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<REPLACEABLE CLASS="PARAMETER">table</replaceable>
</TERM>
<LISTITEM>
<PARA>
          The name of an existing table.
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
<REPLACEABLE CLASS="PARAMETER">column</replaceable>
</TERM>
<LISTITEM>
<PARA>
The name of a column in <REPLACEABLE CLASS="PARAMETER">table</replaceable>.
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
<REPLACEABLE CLASS="PARAMETER">expression</replaceable>
</TERM>
<LISTITEM>
<PARA>
          A valid expression or value to assign to column.
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
<REPLACEABLE CLASS="PARAMETER">fromlist</REPLACEABLE>
</TERM>
<LISTITEM>
<PARA>
          A <productname>Postgres</productname>
 non-standard extension to allow columns
          from other tables to appear in the WHERE condition.
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
<REPLACEABLE CLASS="PARAMETER">condition</REPLACEABLE>
</TERM>
<LISTITEM>
<PARA>
          Refer to the SELECT statement for a further description
          of the WHERE clause.
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>

<REFSECT2 ID="R2-SQL-UPDATE-2">
<REFSECT2INFO>
<DATE>1998-09-24</DATE>
</REFSECT2INFO>
<TITLE>
Outputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
UPDATE <replaceable class="parameter">#</replaceable>
</TERM>
<LISTITEM>
<PARA>
          Message returned if successful.
The <replaceable class="parameter">#</replaceable>
          means the number of rows updated.
If <replaceable class="parameter">#</replaceable>
 is equal 0 no rows are updated.
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>

</REFSECT2>
</REFSYNOPSISDIV>

<REFSECT1 ID="R1-SQL-UPDATE-1">
<REFSECT1INFO>
<DATE>1998-09-24</DATE>
</REFSECT1INFO>
<TITLE>
Description
</TITLE>
<PARA>
   UPDATE changes the values of the columns specified for
   all rows which satisfy condition. Only the columns 
   to be modified need appear as column.

<PARA>
   Array references use the same syntax found in SELECT.
   That is, either single array elements, a range of array
   elements or the entire array may be replaced with a single
   query.

<PARA>
   You must have write access to the table in order to modify
   it, as well as read access to any table whose values are
   mentioned in the WHERE condition.
 
</REFSECT1>

<REFSECT1 ID="R1-SQL-UPDATE-2">
<TITLE>
Usage
</TITLE>
<PARA>
</PARA>
<ProgramListing>
   --Change word "Drama" with "Dramatic" on column kind:
   --
   UPDATE films 
      SET kind = 'Dramatic'
      WHERE kind = 'Drama';

   SELECT * FROM films WHERE kind = 'Dramatic' OR kind = 'Drama';

   code |title        |did| date_prod|kind      |len
   -----+-------------+---+----------+----------+------
   BL101|The Third Man|101|1949-12-23|Dramatic  | 01:44
   P_302|Becket       |103|1964-02-03|Dramatic  | 02:28
   M_401|War and Peace|104|1967-02-12|Dramatic  | 05:57
   T_601|Yojimbo      |106|1961-06-16|Dramatic  | 01:50
   DA101|Das Boot     |110|1981-11-11|Dramatic  | 02:29
</ProgramListing>

</REFSECT1>

<REFSECT1 ID="R1-SQL-UPDATE-3">
<TITLE>
Compatibility
</TITLE>
<PARA>
</PARA>

<REFSECT2 ID="R2-SQL-UPDATE-4">
<REFSECT2INFO>
<DATE>1998-09-24</DATE>
</REFSECT2INFO>
<TITLE>
SQL92
</TITLE>
<PARA>
   SQL92 defines a different syntax for positioned UPDATE statement:

<programlisting>
   UPDATE table SET column = expression [, ...]
          WHERE CURRENT OF <replaceable class="parameter">cursor</replaceable>
</programlisting>

   where <replaceable class="parameter">cursor</replaceable>
 identifies an open cursor.
</REFENTRY>
