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Bug#14654 : Cannot select from the same table twice within a UNION statement

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Made the parser to support parenthesis around UNION branches.
 This is done by amending the rules of the parser so it generates the correct
 structure.
 Currently it supports arbitrary subquery/join/parenthesis operations in the 
 EXISTS clause. 
 In the IN/scalar subquery case it will allow adding nested parenthesis only 
 if there is an UNION clause after the parenthesis. Otherwise it will just  
 treat the multiple nested parenthesis as a scalar expression.
 It adds extra lex level for ((SELECT ...) UNION ...) to accommodate for the
 UNION clause.
This commit is contained in:
gkodinov/kgeorge@macbook.gmz
2006-08-31 18:00:25 +03:00
parent 270629a158
commit e5bc4c7e77
3 changed files with 125 additions and 72 deletions
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25
mysql-test/r/subselect.result
View File

@ -3346,3 +3346,28 @@ ORDER BY t1.t DESC LIMIT 1);
i1 i2 t i1 i2 t
24 1 2005-05-27 12:40:30 24 1 2006-06-20 12:29:40
DROP TABLE t1, t2;
CREATE TABLE t1 (i INT);
(SELECT i FROM t1) UNION (SELECT i FROM t1);
i
SELECT sql_no_cache * FROM t1 WHERE NOT EXISTS
(
(SELECT i FROM t1) UNION
(SELECT i FROM t1)
);
i
SELECT * FROM t1
WHERE NOT EXISTS (((SELECT i FROM t1) UNION (SELECT i FROM t1)));
i
explain select ((select t11.i from t1 t11) union (select t12.i from t1 t12))
from t1;
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'union (select t12.i from t1 t12))
from t1' at line 1
explain select * from t1 where not exists
((select t11.i from t1 t11) union (select t12.i from t1 t12));
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 system NULL NULL NULL NULL 0 const row not found
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL No tables used
3 SUBQUERY NULL NULL NULL NULL NULL NULL NULL no matching row in const table
4 UNION t12 system NULL NULL NULL NULL 0 const row not found
NULL UNION RESULT <union2,4> ALL NULL NULL NULL NULL NULL
DROP TABLE t1;