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SQL:2008 alternative syntax for LIMIT/OFFSET:

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OFFSET num {ROW|ROWS} FETCH {FIRST|NEXT} [num] {ROW|ROWS} ONLY
This commit is contained in:
Peter Eisentraut
2008-10-22 11:00:34 +00:00
parent e6ae3b5dbf
commit 361bfc3572
6 changed files with 108 additions and 27 deletions
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18
src/backend/catalog/sql_features.txt
View File

@ -319,15 +319,15 @@ F851 <order by clause> in subqueries YES
F852 Top-level <order by clause> in views YES
F855 Nested <order by clause> in <query expression> YES
F856 Nested <fetch first clause> in <query expression> YES
F857 Top-level <fetch first clause> in <query expression> NO same as LIMIT
F858 <fetch first clause> in subqueries NO same as LIMIT
F859 Top-level <fetch first clause> in views NO same as LIMIT
F860 <fetch first row count> in <fetch first clause> NO same as LIMIT
F861 Top-level <result offset clause> in <query expression> NO same as OFFSET
F862 <result offset clause> in subqueries NO same as OFFSET
F863 Nested <result offset clause> in <query expression> NO same as OFFSET
F864 Top-level <result offset clause> in views NO same as OFFSET
F865 <offset row count> in <result offset clause> NO same as OFFSET
F857 Top-level <fetch first clause> in <query expression> YES
F858 <fetch first clause> in subqueries YES
F859 Top-level <fetch first clause> in views YES
F860 <fetch first row count> in <fetch first clause> YES
F861 Top-level <result offset clause> in <query expression> YES
F862 <result offset clause> in subqueries YES
F863 Nested <result offset clause> in <query expression> YES
F864 Top-level <result offset clause> in views YES
F865 <offset row count> in <result offset clause> YES
S011 Distinct data types NO
S011 Distinct data types 01 USER_DEFINED_TYPES view NO
S023 Basic structured types NO

44
src/backend/parser/gram.y
View File

@ -11,7 +11,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.627 2008/10/21 08:38:15 petere Exp $
* $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.628 2008/10/22 11:00:34 petere Exp $
*
* HISTORY
* AUTHOR DATE MAJOR EVENT
@ -308,6 +308,8 @@ static TypeName *TableFuncTypeName(List *columns);
%type <objtype> reindex_type drop_type comment_type
%type <node> fetch_direction select_limit_value select_offset_value
select_offset_value2 opt_select_fetch_first_value
%type <ival> row_or_rows first_or_next
%type <list> OptSeqOptList SeqOptList
%type <defelt> SeqOptElem
@ -6579,6 +6581,13 @@ select_limit:
errhint("Use separate LIMIT and OFFSET clauses."),
scanner_errposition(@1)));
}
/* SQL:2008 syntax variants */
| OFFSET select_offset_value2 row_or_rows
{ $$ = list_make2($2, NULL); }
| FETCH first_or_next opt_select_fetch_first_value row_or_rows ONLY
{ $$ = list_make2(NULL, $3); }
| OFFSET select_offset_value2 row_or_rows FETCH first_or_next opt_select_fetch_first_value row_or_rows ONLY
{ $$ = list_make2($2, $6); }
;
opt_select_limit:
@ -6596,10 +6605,40 @@ select_limit_value:
}
;
/*
* Allowing full expressions without parentheses causes various parsing
* problems with the trailing ROW/ROWS key words. SQL only calls for
* constants, so we allow the rest only with parentheses.
*/
opt_select_fetch_first_value:
SignedIconst { $$ = makeIntConst($1, @1); }
| '(' a_expr ')' { $$ = $2; }
| /*EMPTY*/ { $$ = makeIntConst(1, -1); }
;
select_offset_value:
a_expr { $$ = $1; }
;
/*
* Again, the trailing ROW/ROWS in this case prevent the full expression
* syntax. c_expr is the best we can do.
*/
select_offset_value2:
c_expr { $$ = $1; }
;
/* noise words */
row_or_rows:
ROW { $$ = 0; }
| ROWS { $$ = 0; }
/* noise words */
first_or_next:
FIRST_P { $$ = 0; }
| NEXT { $$ = 0; }
group_clause:
GROUP_P BY expr_list { $$ = $3; }
| /*EMPTY*/ { $$ = NIL; }
@ -9218,6 +9257,7 @@ Sconst: SCONST { $$ = $1; };
RoleId: ColId { $$ = $1; };
SignedIconst: ICONST { $$ = $1; }
| '+' ICONST { $$ = + $2; }
| '-' ICONST { $$ = - $2; }
;
@ -9351,7 +9391,6 @@ unreserved_keyword:
| EXPLAIN
| EXTERNAL
| FAMILY
| FETCH
| FIRST_P
| FORCE
| FORWARD
@ -9641,6 +9680,7 @@ reserved_keyword:
| END_P
| EXCEPT
| FALSE_P
| FETCH
| FOR
| FOREIGN
| FROM

4
src/backend/parser/keywords.c
View File

@ -11,7 +11,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/parser/keywords.c,v 1.203 2008/10/21 08:38:15 petere Exp $
* $PostgreSQL: pgsql/src/backend/parser/keywords.c,v 1.204 2008/10/22 11:00:34 petere Exp $
*
*-------------------------------------------------------------------------
*/
@ -166,7 +166,7 @@ const ScanKeyword ScanKeywords[] = {
{"extract", EXTRACT, COL_NAME_KEYWORD},
{"false", FALSE_P, RESERVED_KEYWORD},
{"family", FAMILY, UNRESERVED_KEYWORD},
{"fetch", FETCH, UNRESERVED_KEYWORD},
{"fetch", FETCH, RESERVED_KEYWORD},
{"first", FIRST_P, UNRESERVED_KEYWORD},
{"float", FLOAT_P, COL_NAME_KEYWORD},
{"for", FOR, RESERVED_KEYWORD},