<tbody>

<row>

<entry role="func_table_entry"><para role="func_signature">

<entryid="merge-action"role="func_table_entry"><para role="func_signature">

<indexterm>

<primary>merge_action</primary>

</indexterm>

<function id="merge_action">merge_action</function> ( )

<function>merge_action</function> ( )

<returnvalue>text</returnvalue>

</para>

<para>

The optional <literal>RETURNING</literal> clause causes <command>MERGE</command>

to compute and return value(s) based on each row inserted, updated, or

deleted. Any expression using the source or target table's columns, or

the <xref linkend="merge_action"/> function can be computed. When an

<command>INSERT</command> or <command>UPDATE</command> action is performed,

the new values of the target table's columns are used. When a

<command>DELETE</command> is performed, the old values of the target table's

columns are used. The syntax of the <literal>RETURNING</literal> list is

identical to that of the output list of <command>SELECT</command>.

the <link linkend="merge-action"><function>merge_action()</function></link>

function can be computed. When an <command>INSERT</command> or

<command>UPDATE</command> action is performed, the new values of the target

table's columns are used. When a <command>DELETE</command> is performed,

the old values of the target table's columns are used. The syntax of the

<literal>RETURNING</literal> list is identical to that of the output list

of <command>SELECT</command>.

</para>

<para>

An expression to be computed and returned by the <command>MERGE</command>

command after each row is changed (whether inserted, updated, or deleted).

The expression can use any columns of the source or target tables, or the

<xref linkend="merge_action"/>function to return additional information

about the action executed.

<link linkend="merge-action"><function>merge_action()</function></link>

function to return additional informationabout the action executed.

</para>

<para>

Writing <literal>*</literal> will return all columns from the source