diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/ref/merge.sgml | 36 |
1 files changed, 28 insertions, 8 deletions
diff --git a/doc/src/sgml/ref/merge.sgml b/doc/src/sgml/ref/merge.sgml index 7a8ac40259c..e745fbd5867 100644 --- a/doc/src/sgml/ref/merge.sgml +++ b/doc/src/sgml/ref/merge.sgml @@ -44,7 +44,9 @@ INSERT [( <replaceable class="parameter">column_name</replaceable> [, ...] )] <phrase>and <replaceable class="parameter">merge_update</replaceable> is:</phrase> UPDATE SET { <replaceable class="parameter">column_name</replaceable> = { <replaceable class="parameter">expression</replaceable> | DEFAULT } | - ( <replaceable class="parameter">column_name</replaceable> [, ...] ) = ( { <replaceable class="parameter">expression</replaceable> | DEFAULT } [, ...] ) } [, ...] + ( <replaceable class="parameter">column_name</replaceable> [, ...] ) = [ ROW ] ( { <replaceable class="parameter">expression</replaceable> | DEFAULT } [, ...] ) | + ( <replaceable class="parameter">column_name</replaceable> [, ...] ) = ( <replaceable class="parameter">sub-SELECT</replaceable> ) + } [, ...] <phrase>and <replaceable class="parameter">merge_delete</replaceable> is:</phrase> @@ -129,6 +131,19 @@ DELETE <variablelist> <varlistentry> + <term><replaceable class="parameter">with_query</replaceable></term> + <listitem> + <para> + The <literal>WITH</literal> clause allows you to specify one or more + subqueries that can be referenced by name in the <command>MERGE</command> + query. See <xref linkend="queries-with"/> and <xref linkend="sql-select"/> + for details. Note that <literal>WITH RECURSIVE</literal> is not supported + by <command>MERGE</command>. + </para> + </listitem> + </varlistentry> + + <varlistentry> <term><replaceable class="parameter">target_table_name</replaceable></term> <listitem> <para> @@ -393,9 +408,10 @@ DELETE An expression to assign to the column. If used in a <literal>WHEN MATCHED</literal> clause, the expression can use values from the original row in the target table, and values from the - <replaceable>data_source</replaceable> row. + <replaceable class="parameter">data_source</replaceable> row. If used in a <literal>WHEN NOT MATCHED</literal> clause, the - expression can use values from the <replaceable>data_source</replaceable>. + expression can use values from the + <replaceable class="parameter">data_source</replaceable> row. </para> </listitem> </varlistentry> @@ -411,13 +427,17 @@ DELETE </varlistentry> <varlistentry> - <term><replaceable class="parameter">with_query</replaceable></term> + <term><replaceable class="parameter">sub-SELECT</replaceable></term> <listitem> <para> - The <literal>WITH</literal> clause allows you to specify one or more - subqueries that can be referenced by name in the <command>MERGE</command> - query. See <xref linkend="queries-with"/> and <xref linkend="sql-select"/> - for details. + A <literal>SELECT</literal> sub-query that produces as many output columns + as are listed in the parenthesized column list preceding it. The + sub-query must yield no more than one row when executed. If it + yields one row, its column values are assigned to the target columns; + if it yields no rows, NULL values are assigned to the target columns. + The sub-query can refer to values from the original row in the target table, + and values from the <replaceable class="parameter">data_source</replaceable> + row. </para> </listitem> </varlistentry> |