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Code Issues

CORE-4526 Support for SQL:2008 OFFSET and FETCH clauses

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This commit is contained in:
mrotteveel 2014-11-29 15:39:59 +00:00
parent 6f45339b62
commit 155508d05e
6 changed files with 145 additions and 21 deletions
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53
doc/sql.extensions/README.offset_fetch.txt Normal file
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@ -0,0 +1,53 @@
-----------------------
OFFSET and FETCH clause
-----------------------
Function:
SQL:2008 compliant equivalent for FIRST/SKIP, and an alternative for ROWS.
The OFFSET clause specifies the number of rows to skip. The FETCH clause
specifies the number of rows to fetch.
OFFSET and FETCH can be applied independently on top-level and nested query
expressions.
Author:
Mark Rotteveel <mrotteveel@users.sourceforge.net>
Syntax rules:
SELECT ... [ ORDER BY <expr_list> ]
[ OFFSET <simple_value_expr> { ROW | ROWS } ]
[ FETCH { FIRST | NEXT } [ <simple_value_expr> ] { ROW | ROWS } ONLY ]
Where <simple_value_expr> is a (numeric) literal, a SQL parameter (?) or
PSQL named parameter (:namedparameter).
Scope:
DSQL, PSQL
Example(s):
1. SELECT * FROM T1
ORDER BY COL1
OFFSET 10 ROWS
2. SELECT * FROM T1
ORDER BY COL1
FETCH FIRST 10 ROWS ONLY
3. SELECT * FROM (
SELECT * FROM T1
ORDER BY COL1 DESC
OFFSET 1 ROW
FETCH NEXT 10 ROWS ONLY
) a
ORDER BY a.COL1
FETCH FIRST ROW ONLY
Note(s):
1. Firebird doesn't support the percentage FETCH defined in the SQL
standard.
2. Firebird doesn't support the FETCH ... WITH TIES defined in the SQL
standard.
3. The FIRST/SKIP and ROWS clause are non-standard alternatives.
4. The OFFSET and/or FETCH clauses cannot be combined with ROWS or
FIRST/SKIP on the same query expression.
5. Expressions, column references, etc are not allowed within either clause.
6. Contrary to the ROWS clause, OFFSET and FETCH are only available on
SELECT statements.

22
doc/sql.extensions/README.rows
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@ -3,8 +3,9 @@ ROWS clause
-----------
Function:
Allow to limit a number of rows retrieved from a select expression. For a highest level
select statement, it would mean a number of rows sent to the host program.
Limits the number of rows retrieved from a select expression. For the
top-level select statement, it would mean a number of rows sent to the host
program.
Author:
Dmitry Yemanov <yemanov@yandex.ru>
@ -28,10 +29,13 @@ ROWS clause
ROWS 1
Note(s):
1. ROWS is a more understandable alternative to the FIRST/SKIP clauses with some extra benefits.
It can be used in unions and all kind of subqueries. Also it's available in the UPDATE/DELETE
statements.
2. When <expr2> is omitted, then ROWS <expr1> is a semantical equivalent for FIRST <expr1>. When
both <expr1> and <expr2> are used, then ROWS <expr1> TO <expr2> means:
FIRST (<expr2> - <expr1> + 1) SKIP (<expr1> - 1). Note that there's no semantical equivalent
for a SKIP clause used without a FIRST clause.
1. ROWS is a more understandable alternative to the FIRST/SKIP clauses with
some extra benefits. It can be used in unions and all kind of subqueries.
It is also available in the UPDATE/DELETE statements.
2. When <expr2> is omitted, then ROWS <expr1> is a semantical equivalent for
FIRST <expr1>. When both <expr1> and <expr2> are used, then ROWS <expr1>
TO <expr2> means:
FIRST (<expr2> - <expr1> + 1) SKIP (<expr1> - 1). Note that there's no
semantic equivalent for a SKIP clause used without a FIRST clause.
3. The ROWS-clause is not defined in the SQL standard. For SELECT, consider
the alternative OFFSET and FETCH clauses defined in the SQL standard.

77
src/dsql/parse.y
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@ -570,6 +570,8 @@ using namespace Firebird;
%token <metaNamePtr> SERVERWIDE
%token <metaNamePtr> INCREMENT
%token <metaNamePtr> TRUSTED
%token <metaNamePtr> ROW
%token <metaNamePtr> OFFSET
// precedence declarations for expression evaluation
@ -3809,9 +3811,11 @@ keyword_or_column
| KW_BOOLEAN // added in FB 3.0
| DETERMINISTIC
| KW_FALSE
| OFFSET
| OVER
| RETURN
| RDB_RECORD_VERSION
| ROW
| SCROLL
| SQLSTATE
| KW_TRUE
@ -4898,6 +4902,21 @@ select_expr
node->rowsClause = $4;
node->withClause = $1;
}
| with_clause select_expr_body order_clause result_offset_clause fetch_first_clause
{
SelectExprNode* node = $$ = newNode<SelectExprNode>();
node->querySpec = $2;
node->orderClause = $3;
if ($4 || $5) {
RowsClause* rowsNode = newNode<RowsClause>();
rowsNode->skip = $4;
rowsNode->length = $5;
node->rowsClause = rowsNode;
} else {
node->rowsClause = NULL;
}
node->withClause = $1;
}
;
%type <withClause> with_clause
@ -5451,14 +5470,13 @@ nulls_placement
| LAST { $$ = OrderNode::NULLS_LAST; }
;
// ROWS clause
// ROWS clause - ROWS clause is a non-standard alternative to OFFSET .. FETCH ..
// Non-optional - for use in select_expr (so it doesn't cause conflicts with OFFSET .. FETCH ..)
%type <rowsClause> rows_clause
rows_clause
: // nothing
{ $$ = NULL; }
// equivalent to FIRST value
| ROWS value
: ROWS value
{
$$ = newNode<RowsClause>();
$$->length = $2;
@ -5473,6 +5491,45 @@ rows_clause
}
;
// Optional - for use in delete_searched and update_searched
%type <rowsClause> rows_clause_optional
rows_clause_optional
: // nothing
{ $$ = NULL; }
| rows_clause
;
// OFFSET n {ROW | ROWS}
row_noise
: ROW
| ROWS
;
%type <valueExprNode> result_offset_clause
result_offset_clause
: // nothing
{ $$ = NULL; }
| OFFSET simple_value_spec row_noise
{ $$ = $2; }
;
// FETCH {FIRST | NEXT} [ n ] {ROW | ROWS} ONLY
first_next_noise
: FIRST
| NEXT
;
%type <valueExprNode> fetch_first_clause
fetch_first_clause
: // nothing
{ $$ = NULL; }
| FETCH first_next_noise simple_value_spec row_noise ONLY
{ $$ = $3; }
| FETCH first_next_noise row_noise ONLY
{ $$ = MAKE_const_slong(1); }
;
// INSERT statement
// IBO hack: replace column_parens_opt by ins_column_parens_opt.
@ -5588,7 +5645,7 @@ delete
%type <stmtNode> delete_searched
delete_searched
: KW_DELETE FROM table_name where_clause plan_clause order_clause rows_clause returning_clause
: KW_DELETE FROM table_name where_clause plan_clause order_clause rows_clause_optional returning_clause
{
EraseNode* node = newNode<EraseNode>();
node->dsqlRelation = $3;
@ -5625,7 +5682,7 @@ update
%type <stmtNode> update_searched
update_searched
: UPDATE table_name SET assignments where_clause plan_clause
order_clause rows_clause returning_clause
order_clause rows_clause_optional returning_clause
{
ModifyNode* node = newNode<ModifyNode>();
node->dsqlRelation = $2;
@ -6344,6 +6401,14 @@ value_primary
| '(' value_primary ')' { $$ = $2; }
;
// Matches definition of <simple value specification> in SQL standard
%type <valueExprNode> simple_value_spec
simple_value_spec
: constant
| variable
| parameter
;
%type <valueExprNode> nonparenthesized_value
nonparenthesized_value
: column_name

6
src/include/gen/msgs.h
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@ -518,8 +518,8 @@ static const struct {
{335544814, "Services functionality will be supported in a later version of the product"}, /* service_not_supported */
{335544815, "GENERATOR @1"}, /* generator_name */
{335544816, "UDF @1"}, /* udf_name */
{335544817, "Invalid parameter to FIRST. Only integers >= 0 are allowed."}, /* bad_limit_param */
{335544818, "Invalid parameter to SKIP. Only integers >= 0 are allowed."}, /* bad_skip_param */
{335544817, "Invalid parameter to FETCH or FIRST. Only integers >= 0 are allowed."}, /* bad_limit_param */
{335544818, "Invalid parameter to OFFSET or SKIP. Only integers >= 0 are allowed."}, /* bad_skip_param */
{335544819, "File exceeded maximum size of 2GB. Add another database file or use a 64 bit I/O version of Firebird."}, /* io_32bit_exceeded_err */
{335544820, "Unable to find savepoint with name @1 in transaction context"}, /* invalid_savepoint */
{335544821, "Invalid column position used in the @1 clause"}, /* dsql_column_pos_err */
@ -1158,7 +1158,7 @@ Data source : @4"}, /* eds_statement */
{336397324, "CREATE GENERATOR @1 failed"}, /* dsql_create_generator_failed */
{336397325, "SET GENERATOR @1 failed"}, /* dsql_set_generator_failed */
{336397326, "WITH LOCK can be used only with a single physical table"}, /* dsql_wlock_simple */
{336397327, "FIRST/SKIP cannot be used with ROWS"}, /* dsql_firstskip_rows */
{336397327, "FIRST/SKIP cannot be used with OFFSET/FETCH or ROWS"}, /* dsql_firstskip_rows */
{336397328, "WITH LOCK cannot be used with aggregates"}, /* dsql_wlock_aggregates */
{336397329, "WITH LOCK cannot be used with @1"}, /* dsql_wlock_conflict */
{336723983, "unable to open database"}, /* gsec_cant_open_db */

6
src/msgs/messages2.sql
View File

@ -593,8 +593,8 @@ without specifying a character set.', NULL);
('service_not_supported', 'SVC_attach', 'svc.c', NULL, 0, 494, NULL, 'Services functionality will be supported in a later version of the product', NULL, NULL);
('generator_name', 'check_dependencies', 'dfw.e', NULL, 0, 495, NULL, 'GENERATOR @1', NULL, NULL);
('udf_name', 'check_dependencies', 'dfw.e', NULL, 0, 496, NULL, 'UDF @1', NULL, NULL);
('bad_limit_param', 'RSE_open', 'rse.c', NULL, 0, 497, NULL, 'Invalid parameter to FIRST. Only integers >= 0 are allowed.', NULL, NULL);
('bad_skip_param', 'RSE_open', 'rse.c', NULL, 0, 498, NULL, 'Invalid parameter to SKIP. Only integers >= 0 are allowed.', NULL, NULL);
('bad_limit_param', 'RSE_open', 'rse.c', NULL, 0, 497, NULL, 'Invalid parameter to FETCH or FIRST. Only integers >= 0 are allowed.', NULL, NULL);
('bad_skip_param', 'RSE_open', 'rse.c', NULL, 0, 498, NULL, 'Invalid parameter to OFFSET or SKIP. Only integers >= 0 are allowed.', NULL, NULL);
('io_32bit_exceeded_err', 'seek_file', 'unix.c', NULL, 0, 499, NULL, 'File exceeded maximum size of 2GB. Add another database file or use a 64 bit I/O version of Firebird.', NULL, NULL);
('invalid_savepoint', 'looper', 'exe.cpp', NULL, 0, 500, NULL, 'Unable to find savepoint with name @1 in transaction context', NULL, NULL);
('dsql_column_pos_err', '(several)', 'pass1.cpp', NULL, 0, 501, NULL, 'Invalid column position used in the @1 clause', NULL, NULL);
@ -2607,7 +2607,7 @@ ERROR: Backup incomplete', NULL, NULL);
('dsql_create_generator_failed', 'putErrorPrefix', 'DdlNodes.h', NULL, 13, 1036, NULL, 'CREATE GENERATOR @1 failed', NULL, NULL);
('dsql_set_generator_failed', 'putErrorPrefix', 'DdlNodes.h', NULL, 13, 1037, NULL, 'SET GENERATOR @1 failed', NULL, NULL);
('dsql_wlock_simple', 'pass1_rse_impl', 'pass1.cpp', NULL, 13, 1038, NULL, 'WITH LOCK can be used only with a single physical table', NULL, NULL);
('dsql_firstskip_rows', 'pass1_rse_impl', 'pass1.cpp', NULL, 13, 1039, NULL, 'FIRST/SKIP cannot be used with ROWS', NULL, NULL);
('dsql_firstskip_rows', 'pass1_rse_impl', 'pass1.cpp', NULL, 13, 1039, NULL, 'FIRST/SKIP cannot be used with OFFSET/FETCH or ROWS', NULL, NULL);
('dsql_wlock_aggregates', 'pass1_rse_impl', 'pass1.cpp', NULL, 13, 1040, NULL, 'WITH LOCK cannot be used with aggregates', NULL, NULL);
('dsql_wlock_conflict', NULL, 'pass1.cpp', NULL, 13, 1041, NULL, 'WITH LOCK cannot be used with @1', NULL, NULL);
-- SQLWARN

2
src/yvalve/keywords.cpp
View File

@ -283,6 +283,7 @@ static const TOK tokens[] =
{KW_NUMERIC, "NUMERIC", 1, false},
{OCTET_LENGTH, "OCTET_LENGTH", 2, false},
{OF, "OF", 1, false},
{OFFSET, "OFFSET", 2, false},
{ON, "ON", 1, false},
{ONLY, "ONLY", 1, false},
{OPEN, "OPEN", 2, false},
@ -348,6 +349,7 @@ static const TOK tokens[] =
{ROLE, "ROLE", 1, true},
{ROLLBACK, "ROLLBACK", 1, false},
{ROUND, "ROUND", 2, false},
{ROW, "ROW", 2, false},
{ROW_COUNT, "ROW_COUNT", 2, false},
{ROW_NUMBER, "ROW_NUMBER", 2, false},
{ROWS, "ROWS", 2, false},