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Commit 6077db9

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bmomjianbmomjian
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Allow FOR UPDATE to appear after LIMIT/OFFSET to match MySQL syntax and as
a more logical ordering.
1 parent 8e4357d commit 6077db9

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4 files changed

+43
-32
lines changed

4 files changed

+43
-32
lines changed

‎doc/src/sgml/ref/select.sgml

Lines changed: 16 additions & 16 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
<!--
2-
$Header: /cvsroot/pgsql/doc/src/sgml/ref/select.sgml,v 1.56 2002/08/15 02:59:18 momjian Exp $
2+
$Header: /cvsroot/pgsql/doc/src/sgml/ref/select.sgml,v 1.57 2002/08/28 14:35:37 momjian Exp $
33
PostgreSQL documentation
44
-->
55

@@ -28,9 +28,9 @@ SELECT [ ALL | DISTINCT [ ON ( <replaceable class="PARAMETER">expression</replac
2828
[ HAVING <replaceable class="PARAMETER">condition</replaceable> [, ...] ]
2929
[ { UNION | INTERSECT | EXCEPT } [ ALL ] <replaceable class="PARAMETER">select</replaceable> ]
3030
[ ORDER BY <replaceable class="PARAMETER">expression</replaceable> [ ASC | DESC | USING <replaceable class="PARAMETER">operator</replaceable> ] [, ...] ]
31-
[ FOR UPDATE [ OF <replaceable class="PARAMETER">tablename</replaceable> [, ...] ] ]
3231
[ LIMIT { <replaceable class="PARAMETER">count</replaceable> | ALL } ]
3332
[ OFFSET <replaceable class="PARAMETER">start</replaceable> ]
33+
[ FOR UPDATE [ OF <replaceable class="PARAMETER">tablename</replaceable> [, ...] ] ]
3434

3535
where <replaceable class="PARAMETER">from_item</replaceable> can be:
3636

@@ -107,9 +107,9 @@ where <replaceable class="PARAMETER">from_item</replaceable> can be:
107107
<term><replaceable class="PARAMETER">select</replaceable></term>
108108
<listitem>
109109
<para>
110-
A select statement with all features except the ORDER BY, FOR UPDATE,
111-
and LIMIT clauses (even those can be used when the select is
112-
parenthesized).
110+
A select statement with all features except the ORDER BY,
111+
LIMIT/OFFSET, and FOR UPDATE clauses (even those can be used when the
112+
select is parenthesized).
113113
</para>
114114
</listitem>
115115
</varlistentry>
@@ -354,17 +354,17 @@ where <replaceable class="PARAMETER">from_item</replaceable> can be:
354354
(See <xref linkend="sql-except" endterm="sql-except-title">.)
355355
</para>
356356

357-
<para>
358-
The FOR UPDATE clause allows the SELECT statement to perform
359-
exclusive locking of selected rows.
360-
</para>
361-
362357
<para>
363358
The LIMIT clause allows a subset of the rows produced by the query
364359
to be returned to the user.
365360
(See <xref linkend="sql-limit" endterm="sql-limit-title">.)
366361
</para>
367362

363+
<para>
364+
The FOR UPDATE clause allows the SELECT statement to perform
365+
exclusive locking of selected rows.
366+
</para>
367+
368368
<para>
369369
You must have SELECT privilege to a table to read its values
370370
(See the <command>GRANT</command>/<command>REVOKE</command> statements).
@@ -666,8 +666,8 @@ SELECT name FROM distributors ORDER BY code;
666666

667667
where
668668
<replaceable class="PARAMETER">table_query</replaceable>
669-
specifies any select expression without an ORDER BY, FOR UPDATE,
670-
or LIMIT clause. (ORDER BY and LIMIT can be attached to a sub-expression
669+
specifies any select expression without an ORDER BY, LIMIT, or FOR UPDATE
670+
clause. (ORDER BY and LIMIT can be attached to a sub-expression
671671
if it is enclosed in parentheses. Without parentheses, these clauses
672672
will be taken to apply to the result of the UNION, not to its right-hand
673673
input expression.)
@@ -716,8 +716,8 @@ SELECT name FROM distributors ORDER BY code;
716716

717717
where
718718
<replaceable class="PARAMETER">table_query</replaceable>
719-
specifies any select expression without an ORDER BY, FOR UPDATE,
720-
or LIMIT clause.
719+
specifies any select expression without an ORDER BY, LIMIT, or
720+
FOR UPDATE clause.
721721
</para>
722722

723723
<para>
@@ -757,8 +757,8 @@ SELECT name FROM distributors ORDER BY code;
757757

758758
where
759759
<replaceable class="PARAMETER">table_query</replaceable>
760-
specifies any select expression without an ORDER BY, FOR UPDATE,
761-
or LIMIT clause.
760+
specifies any select expression without an ORDER BY, LIMIT,
761+
or FOR UPDATE clause.
762762
</para>
763763

764764
<para>

‎doc/src/sgml/ref/select_into.sgml

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
<!--
2-
$Header: /cvsroot/pgsql/doc/src/sgml/ref/select_into.sgml,v 1.18 2002/04/23 02:07:16 tgl Exp $
2+
$Header: /cvsroot/pgsql/doc/src/sgml/ref/select_into.sgml,v 1.19 2002/08/28 14:35:37 momjian Exp $
33
PostgreSQL documentation
44
-->
55

@@ -29,9 +29,9 @@ SELECT [ ALL | DISTINCT [ ON ( <replaceable class="PARAMETER">expression</replac
2929
[ HAVING <replaceable class="PARAMETER">condition</replaceable> [, ...] ]
3030
[ { UNION | INTERSECT | EXCEPT } [ ALL ] <replaceable class="PARAMETER">select</replaceable> ]
3131
[ ORDER BY <replaceable class="PARAMETER">expression</replaceable> [ ASC | DESC | USING <replaceable class="PARAMETER">operator</replaceable> ] [, ...] ]
32-
[ FOR UPDATE [ OF <replaceable class="PARAMETER">tablename</replaceable> [, ...] ] ]
3332
[ LIMIT [ <replaceable class="PARAMETER">start</replaceable> , ] { <replaceable class="PARAMETER">count</replaceable> | ALL } ]
3433
[ OFFSET <replaceable class="PARAMETER">start</replaceable> ]
34+
[ FOR UPDATE [ OF <replaceable class="PARAMETER">tablename</replaceable> [, ...] ] ]
3535

3636
where <replaceable class="PARAMETER">from_item</replaceable> can be:
3737

‎doc/src/sgml/sql.sgml

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
<!--
2-
$Header: /cvsroot/pgsql/doc/src/sgml/sql.sgml,v 1.26 2002/03/15 16:16:31 momjian Exp $
2+
$Header: /cvsroot/pgsql/doc/src/sgml/sql.sgml,v 1.27 2002/08/28 14:35:36 momjian Exp $
33
-->
44

55
<chapter id="sql">
@@ -863,9 +863,9 @@ SELECT [ ALL | DISTINCT [ ON ( <replaceable class="PARAMETER">expression</replac
863863
[ HAVING <replaceable class="PARAMETER">condition</replaceable> [, ...] ]
864864
[ { UNION | INTERSECT | EXCEPT } [ ALL ] <replaceable class="PARAMETER">select</replaceable> ]
865865
[ ORDER BY <replaceable class="PARAMETER">expression</replaceable> [ ASC | DESC | USING <replaceable class="PARAMETER">operator</replaceable> ] [, ...] ]
866-
[ FOR UPDATE [ OF <replaceable class="PARAMETER">class_name</replaceable> [, ...] ] ]
867866
[ LIMIT { <replaceable class="PARAMETER">count</replaceable> | ALL } ]
868867
[ OFFSET <replaceable class="PARAMETER">start</replaceable> ]
868+
[ FOR UPDATE [ OF <replaceable class="PARAMETER">class_name</replaceable> [, ...] ] ]
869869
</synopsis>
870870
</para>
871871

‎src/backend/parser/gram.y

Lines changed: 23 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -11,7 +11,7 @@
1111
*
1212
*
1313
* IDENTIFICATION
14-
* $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.361 2002/08/27 04:55:08 tgl Exp $
14+
* $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.362 2002/08/28 14:35:37 momjian Exp $
1515
*
1616
* HISTORY
1717
* AUTHOR DATE MAJOR EVENT
@@ -208,8 +208,8 @@ static void doNegateFloat(Value *v);
208208
func_args_list, func_as, createfunc_opt_list
209209
oper_argtypes, RuleActionList, RuleActionMulti,
210210
opt_column_list, columnList, opt_name_list,
211-
sort_clause, sortby_list, index_params, index_list,
212-
name_list, from_clause, from_list, opt_array_bounds,
211+
sort_clause, opt_sort_clause, sortby_list, index_params,
212+
index_list,name_list, from_clause, from_list, opt_array_bounds,
213213
qualified_name_list, any_name, any_name_list,
214214
any_operator, expr_list, dotted_name, attrs,
215215
target_list, update_target_list, insert_column_list,
@@ -4180,24 +4180,30 @@ select_with_parens:
41804180
| '(' select_with_parens ')' { $$ = $2; }
41814181
;
41824182

4183+
/*
4184+
* FOR UPDATE may be before or after LIMIT/OFFSET.
4185+
* In <=7.2.X, LIMIT/OFFSET had to be after FOR UPDATE
4186+
* We now support both orderings, but prefer LIMIT/OFFSET before FOR UPDATE
4187+
* 2002-08-28 bjm
4188+
*/
41834189
select_no_parens:
41844190
simple_select { $$ = $1; }
4185-
| select_clause sort_clause opt_for_update_clause opt_select_limit
4191+
| select_clause sort_clause
41864192
{
4187-
insertSelectOptions((SelectStmt *) $1, $2, $3,
4188-
nth(0, $4), nth(1, $4));
4193+
insertSelectOptions((SelectStmt *) $1, $2, NIL,
4194+
NULL, NULL);
41894195
$$ = $1;
41904196
}
4191-
| select_clause for_update_clause opt_select_limit
4197+
| select_clause opt_sort_clause for_update_clause opt_select_limit
41924198
{
4193-
insertSelectOptions((SelectStmt *) $1, NIL, $2,
4194-
nth(0, $3), nth(1, $3));
4199+
insertSelectOptions((SelectStmt *) $1, $2, $3,
4200+
nth(0, $4), nth(1, $4));
41954201
$$ = $1;
41964202
}
4197-
| select_clause select_limit
4203+
| select_clause opt_sort_clause select_limit opt_for_update_clause
41984204
{
4199-
insertSelectOptions((SelectStmt *) $1, NIL, NIL,
4200-
nth(0, $2), nth(1, $2));
4205+
insertSelectOptions((SelectStmt *) $1, $2, $4,
4206+
nth(0, $3), nth(1, $3));
42014207
$$ = $1;
42024208
}
42034209
;
@@ -4335,6 +4341,11 @@ opt_distinct:
43354341
| /*EMPTY*/ { $$ = NIL; }
43364342
;
43374343

4344+
opt_sort_clause:
4345+
sort_clause { $$ = $1;}
4346+
| /*EMPTY*/ { $$ = NIL; }
4347+
;
4348+
43384349
sort_clause:
43394350
ORDER BY sortby_list { $$ = $3; }
43404351
;

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