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SQL:2008 alternative syntax for LIMIT/OFFSET:
OFFSET num {ROW|ROWS} FETCH {FIRST|NEXT} [num] {ROW|ROWS} ONLY
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Peter Eisentraut
parent
e6ae3b5dbf
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@ -1,5 +1,5 @@
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<!--
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$PostgreSQL: pgsql/doc/src/sgml/ref/select.sgml,v 1.106 2008/10/07 19:27:04 tgl Exp $
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$PostgreSQL: pgsql/doc/src/sgml/ref/select.sgml,v 1.107 2008/10/22 11:00:33 petere Exp $
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PostgreSQL documentation
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-->
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@ -30,7 +30,8 @@ SELECT [ ALL | DISTINCT [ ON ( <replaceable class="parameter">expression</replac
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[ { UNION | INTERSECT | EXCEPT } [ ALL ] <replaceable class="parameter">select</replaceable> ]
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[ ORDER BY <replaceable class="parameter">expression</replaceable> [ ASC | DESC | USING <replaceable class="parameter">operator</replaceable> ] [ NULLS { FIRST | LAST } ] [, ...] ]
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[ LIMIT { <replaceable class="parameter">count</replaceable> | ALL } ]
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[ OFFSET <replaceable class="parameter">start</replaceable> ]
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[ OFFSET <replaceable class="parameter">start</replaceable> [ ROW | ROWS ] ]
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[ FETCH { FIRST | NEXT } [ <replaceable class="parameter">count</replaceable> ] { ROW | ROWS } ONLY ]
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[ FOR { UPDATE | SHARE } [ OF <replaceable class="parameter">table_name</replaceable> [, ...] ] [ NOWAIT ] [...] ]
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where <replaceable class="parameter">from_item</replaceable> can be one of:
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@ -150,7 +151,7 @@ and <replaceable class="parameter">with_query</replaceable> is:
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<listitem>
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<para>
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If the <literal>LIMIT</literal> or <literal>OFFSET</literal>
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If the <literal>LIMIT</literal> (or <literal>FETCH FIRST</literal>) or <literal>OFFSET</literal>
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clause is specified, the <command>SELECT</command> statement
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only returns a subset of the result rows. (See <xref
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linkend="sql-limit" endterm="sql-limit-title"> below.)
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@ -891,6 +892,24 @@ OFFSET <replaceable class="parameter">start</replaceable>
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class="parameter">count</replaceable> rows to be returned.
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</para>
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<para>
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SQL:2008 introduced a different syntax to achieve the same thing,
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which PostgreSQL also supports. It is:
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<synopsis>
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OFFSET <replaceable class="parameter">start</replaceable> { ROW | ROWS }
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FETCH { FIRST | NEXT } [ <replaceable class="parameter">count</replaceable> ] { ROW | ROWS } ONLY
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</synopsis>
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Both clauses are optional, but if present
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the <literal>OFFSET</literal> clause must come before
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the <literal>FETCH</literal> clause. <literal>ROW</literal>
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and <literal>ROWS</literal> as well as <literal>FIRST</literal>
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and <literal>NEXT</literal> are noise words that don't influence
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the effects of these clauses. When using expressions other than
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constants for the offset or fetch count, parentheses will be
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necessary in most cases. If the fetch count is omitted, it
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defaults to 1.
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</para>
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<para>
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When using <literal>LIMIT</>, it is a good idea to use an
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<literal>ORDER BY</> clause that constrains the result rows into a
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@ -1337,13 +1356,30 @@ SELECT distributors.* WHERE distributors.name = 'Westward';
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</para>
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</refsect2>
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<refsect2>
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<title><literal>LIMIT</literal> and <literal>OFFSET</literal></title>
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<para>
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The clauses <literal>LIMIT</literal> and <literal>OFFSET</literal>
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are <productname>PostgreSQL</productname>-specific syntax, also
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used by <productname>MySQL</productname>. The SQL:2008 standard
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has introduced the clauses <literal>OFFSET ... FETCH {FIRST|NEXT}
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...</literal> for the same functionality, as shown above
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in <xref linkend="sql-limit" endterm="sql-limit-title">, and this
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syntax is also used by <productname>IBM DB2</productname>.
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(Applications written for <productname>Oracle</productname>
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frequently use a workaround involving the automatically
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generated <literal>rownum</literal> column, not available in
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PostgreSQL, to implement the effects of these clauses.)
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</para>
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</refsect2>
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<refsect2>
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<title>Nonstandard Clauses</title>
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<para>
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The clauses <literal>DISTINCT ON</literal>,
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<literal>LIMIT</literal>, and <literal>OFFSET</literal> are not
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defined in the SQL standard.
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The clause <literal>DISTINCT ON</literal> is not defined in the
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SQL standard.
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</para>
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</refsect2>
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</refsect1>
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@ -1,5 +1,5 @@
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<!--
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$PostgreSQL: pgsql/doc/src/sgml/ref/select_into.sgml,v 1.41 2008/10/04 21:56:52 tgl Exp $
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$PostgreSQL: pgsql/doc/src/sgml/ref/select_into.sgml,v 1.42 2008/10/22 11:00:34 petere Exp $
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PostgreSQL documentation
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-->
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@ -31,7 +31,8 @@ SELECT [ ALL | DISTINCT [ ON ( <replaceable class="parameter">expression</replac
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[ { UNION | INTERSECT | EXCEPT } [ ALL ] <replaceable class="parameter">select</replaceable> ]
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[ ORDER BY <replaceable class="parameter">expression</replaceable> [ ASC | DESC | USING <replaceable class="parameter">operator</replaceable> ] [ NULLS { FIRST | LAST } ] [, ...] ]
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[ LIMIT { <replaceable class="parameter">count</replaceable> | ALL } ]
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[ OFFSET <replaceable class="parameter">start</replaceable> ]
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[ OFFSET <replaceable class="parameter">start</replaceable> [ ROW | ROWS ] ]
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[ FETCH { FIRST | NEXT } [ <replaceable class="parameter">count</replaceable> ] { ROW | ROWS } ONLY ]
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[ FOR { UPDATE | SHARE } [ OF <replaceable class="parameter">table_name</replaceable> [, ...] ] [ NOWAIT ] [...] ]
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</synopsis>
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</refsynopsisdiv>
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@ -1,5 +1,5 @@
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<!--
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$PostgreSQL: pgsql/doc/src/sgml/ref/values.sgml,v 1.4 2007/02/01 00:28:19 momjian Exp $
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$PostgreSQL: pgsql/doc/src/sgml/ref/values.sgml,v 1.5 2008/10/22 11:00:34 petere Exp $
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PostgreSQL documentation
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-->
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@ -23,7 +23,8 @@ PostgreSQL documentation
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VALUES ( <replaceable class="PARAMETER">expression</replaceable> [, ...] ) [, ...]
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[ ORDER BY <replaceable class="parameter">sort_expression</replaceable> [ ASC | DESC | USING <replaceable class="parameter">operator</replaceable> ] [, ...] ]
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[ LIMIT { <replaceable class="parameter">count</replaceable> | ALL } ]
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[ OFFSET <replaceable class="parameter">start</replaceable> ]
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[ OFFSET <replaceable class="parameter">start</replaceable> [ ROW | ROWS ] ]
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[ FETCH { FIRST | NEXT } [ <replaceable class="parameter">count</replaceable> ] { ROW | ROWS } ONLY ]
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</synopsis>
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</refsynopsisdiv>
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@ -48,8 +49,10 @@ VALUES ( <replaceable class="PARAMETER">expression</replaceable> [, ...] ) [, ..
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<para>
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Within larger commands, <command>VALUES</> is syntactically allowed
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anywhere that <command>SELECT</> is. Because it is treated like a
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<command>SELECT</> by the grammar, it is possible to use the <literal>ORDER
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BY</>, <literal>LIMIT</>, and <literal>OFFSET</> clauses with a
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<command>SELECT</> by the grammar, it is possible to use
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the <literal>ORDER BY</>, <literal>LIMIT</> (or
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equivalently <literal>FETCH FIRST</literal>),
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and <literal>OFFSET</> clauses with a
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<command>VALUES</> command.
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</para>
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</refsect1>
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@ -227,9 +230,10 @@ WHERE ip_address IN (VALUES('192.168.0.1'::inet), ('192.168.0.10'), ('192.168.1.
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<title>Compatibility</title>
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<para>
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<command>VALUES</command> conforms to the SQL standard, except that
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<command>VALUES</command> conforms to the SQL standard.
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<literal>LIMIT</literal> and <literal>OFFSET</literal> are
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<productname>PostgreSQL</productname> extensions.
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<productname>PostgreSQL</productname> extensions; see also
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under <xref linkend="sql-select" endterm="sql-select-title">.
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</para>
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</refsect1>
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@ -319,15 +319,15 @@ F851 <order by clause> in subqueries YES
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F852 Top-level <order by clause> in views YES
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F855 Nested <order by clause> in <query expression> YES
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F856 Nested <fetch first clause> in <query expression> YES
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F857 Top-level <fetch first clause> in <query expression> NO same as LIMIT
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F858 <fetch first clause> in subqueries NO same as LIMIT
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F859 Top-level <fetch first clause> in views NO same as LIMIT
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F860 <fetch first row count> in <fetch first clause> NO same as LIMIT
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F861 Top-level <result offset clause> in <query expression> NO same as OFFSET
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F862 <result offset clause> in subqueries NO same as OFFSET
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F863 Nested <result offset clause> in <query expression> NO same as OFFSET
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F864 Top-level <result offset clause> in views NO same as OFFSET
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F865 <offset row count> in <result offset clause> NO same as OFFSET
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F857 Top-level <fetch first clause> in <query expression> YES
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F858 <fetch first clause> in subqueries YES
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F859 Top-level <fetch first clause> in views YES
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F860 <fetch first row count> in <fetch first clause> YES
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F861 Top-level <result offset clause> in <query expression> YES
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F862 <result offset clause> in subqueries YES
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F863 Nested <result offset clause> in <query expression> YES
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F864 Top-level <result offset clause> in views YES
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F865 <offset row count> in <result offset clause> YES
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S011 Distinct data types NO
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S011 Distinct data types 01 USER_DEFINED_TYPES view NO
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S023 Basic structured types NO
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@ -11,7 +11,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.627 2008/10/21 08:38:15 petere Exp $
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* $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.628 2008/10/22 11:00:34 petere Exp $
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*
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* HISTORY
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* AUTHOR DATE MAJOR EVENT
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@ -308,6 +308,8 @@ static TypeName *TableFuncTypeName(List *columns);
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%type <objtype> reindex_type drop_type comment_type
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%type <node> fetch_direction select_limit_value select_offset_value
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select_offset_value2 opt_select_fetch_first_value
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%type <ival> row_or_rows first_or_next
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%type <list> OptSeqOptList SeqOptList
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%type <defelt> SeqOptElem
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@ -6579,6 +6581,13 @@ select_limit:
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errhint("Use separate LIMIT and OFFSET clauses."),
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scanner_errposition(@1)));
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}
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/* SQL:2008 syntax variants */
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| OFFSET select_offset_value2 row_or_rows
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{ $$ = list_make2($2, NULL); }
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| FETCH first_or_next opt_select_fetch_first_value row_or_rows ONLY
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{ $$ = list_make2(NULL, $3); }
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| OFFSET select_offset_value2 row_or_rows FETCH first_or_next opt_select_fetch_first_value row_or_rows ONLY
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{ $$ = list_make2($2, $6); }
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;
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opt_select_limit:
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@ -6596,10 +6605,40 @@ select_limit_value:
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}
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;
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/*
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* Allowing full expressions without parentheses causes various parsing
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* problems with the trailing ROW/ROWS key words. SQL only calls for
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* constants, so we allow the rest only with parentheses.
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*/
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opt_select_fetch_first_value:
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SignedIconst { $$ = makeIntConst($1, @1); }
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| '(' a_expr ')' { $$ = $2; }
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| /*EMPTY*/ { $$ = makeIntConst(1, -1); }
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;
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select_offset_value:
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a_expr { $$ = $1; }
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;
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/*
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* Again, the trailing ROW/ROWS in this case prevent the full expression
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* syntax. c_expr is the best we can do.
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*/
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select_offset_value2:
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c_expr { $$ = $1; }
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;
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/* noise words */
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row_or_rows:
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ROW { $$ = 0; }
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| ROWS { $$ = 0; }
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/* noise words */
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first_or_next:
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FIRST_P { $$ = 0; }
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| NEXT { $$ = 0; }
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group_clause:
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GROUP_P BY expr_list { $$ = $3; }
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| /*EMPTY*/ { $$ = NIL; }
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@ -9218,6 +9257,7 @@ Sconst: SCONST { $$ = $1; };
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RoleId: ColId { $$ = $1; };
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SignedIconst: ICONST { $$ = $1; }
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| '+' ICONST { $$ = + $2; }
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| '-' ICONST { $$ = - $2; }
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;
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@ -9351,7 +9391,6 @@ unreserved_keyword:
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| EXPLAIN
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| EXTERNAL
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| FAMILY
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| FETCH
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| FIRST_P
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| FORCE
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| FORWARD
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@ -9641,6 +9680,7 @@ reserved_keyword:
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| END_P
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| EXCEPT
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| FALSE_P
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| FETCH
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| FOR
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| FOREIGN
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| FROM
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@ -11,7 +11,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/parser/keywords.c,v 1.203 2008/10/21 08:38:15 petere Exp $
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* $PostgreSQL: pgsql/src/backend/parser/keywords.c,v 1.204 2008/10/22 11:00:34 petere Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -166,7 +166,7 @@ const ScanKeyword ScanKeywords[] = {
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{"extract", EXTRACT, COL_NAME_KEYWORD},
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{"false", FALSE_P, RESERVED_KEYWORD},
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{"family", FAMILY, UNRESERVED_KEYWORD},
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{"fetch", FETCH, UNRESERVED_KEYWORD},
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{"fetch", FETCH, RESERVED_KEYWORD},
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{"first", FIRST_P, UNRESERVED_KEYWORD},
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{"float", FLOAT_P, COL_NAME_KEYWORD},
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{"for", FOR, RESERVED_KEYWORD},
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