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Fixed bug #27932: the function LOCATE returned NULL if any

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of its arguments was evaluated to NULL, while the predicate
LOCATE(str,NULL) IS NULL erroneously was evaluated to FALSE.

This happened because the Item_func_locate::fix_length_and_dec
method by mistake set the value of the maybe_null flag for 
the function item to 0. In consequence of this the function 
was considered as the one that could not ever return NULL.
This commit is contained in:
igor@olga.mysql.com
2007-06-14 18:55:07 -07:00
parent a877145db8
commit 0f0d4720b8
3 changed files with 109 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

76
mysql-test/r/func_str.result
View File

@ -2061,4 +2061,80 @@ C
2707236321 2707236321
DROP TABLE t1, t2; DROP TABLE t1, t2;
DROP VIEW v1; DROP VIEW v1;
SELECT LOCATE('foo', NULL) FROM DUAL;
LOCATE('foo', NULL)
NULL
SELECT LOCATE(NULL, 'o') FROM DUAL;
LOCATE(NULL, 'o')
NULL
SELECT LOCATE(NULL, NULL) FROM DUAL;
LOCATE(NULL, NULL)
NULL
SELECT LOCATE('foo', NULL) IS NULL FROM DUAL;
LOCATE('foo', NULL) IS NULL
1
SELECT LOCATE(NULL, 'o') IS NULL FROM DUAL;
LOCATE(NULL, 'o') IS NULL
1
SELECT LOCATE(NULL, NULL) IS NULL FROM DUAL;
LOCATE(NULL, NULL) IS NULL
1
SELECT ISNULL(LOCATE('foo', NULL)) FROM DUAL;
ISNULL(LOCATE('foo', NULL))
1
SELECT ISNULL(LOCATE(NULL, 'o')) FROM DUAL;
ISNULL(LOCATE(NULL, 'o'))
1
SELECT ISNULL(LOCATE(NULL, NULL)) FROM DUAL;
ISNULL(LOCATE(NULL, NULL))
1
SELECT LOCATE('foo', NULL) <=> NULL FROM DUAL;
LOCATE('foo', NULL) <=> NULL
1
SELECT LOCATE(NULL, 'o') <=> NULL FROM DUAL;
LOCATE(NULL, 'o') <=> NULL
1
SELECT LOCATE(NULL, NULL) <=> NULL FROM DUAL;
LOCATE(NULL, NULL) <=> NULL
1
CREATE TABLE t1 (id int NOT NULL PRIMARY KEY, a varchar(10), p varchar(10));
INSERT INTO t1 VALUES (1, 'foo', 'o');
INSERT INTO t1 VALUES (2, 'foo', NULL);
INSERT INTO t1 VALUES (3, NULL, 'o');
INSERT INTO t1 VALUES (4, NULL, NULL);
SELECT id, LOCATE(a,p) FROM t1;
id LOCATE(a,p)
1 0
2 NULL
3 NULL
4 NULL
SELECT id, LOCATE(a,p) IS NULL FROM t1;
id LOCATE(a,p) IS NULL
1 0
2 1
3 1
4 1
SELECT id, ISNULL(LOCATE(a,p)) FROM t1;
id ISNULL(LOCATE(a,p))
1 0
2 1
3 1
4 1
SELECT id, LOCATE(a,p) <=> NULL FROM t1;
id LOCATE(a,p) <=> NULL
1 0
2 1
3 1
4 1
SELECT id FROM t1 WHERE LOCATE(a,p) IS NULL;
id
2
3
4
SELECT id FROM t1 WHERE LOCATE(a,p) <=> NULL;
id
2
3
4
DROP TABLE t1;
End of 5.0 tests End of 5.0 tests

33
mysql-test/t/func_str.test
View File

@ -1076,4 +1076,37 @@ SELECT * FROM (SELECT * FROM v1) x;
DROP TABLE t1, t2; DROP TABLE t1, t2;
DROP VIEW v1; DROP VIEW v1;
#
# Bug #27932: LOCATE with argument evaluated to NULL
#
SELECT LOCATE('foo', NULL) FROM DUAL;
SELECT LOCATE(NULL, 'o') FROM DUAL;
SELECT LOCATE(NULL, NULL) FROM DUAL;
SELECT LOCATE('foo', NULL) IS NULL FROM DUAL;
SELECT LOCATE(NULL, 'o') IS NULL FROM DUAL;
SELECT LOCATE(NULL, NULL) IS NULL FROM DUAL;
SELECT ISNULL(LOCATE('foo', NULL)) FROM DUAL;
SELECT ISNULL(LOCATE(NULL, 'o')) FROM DUAL;
SELECT ISNULL(LOCATE(NULL, NULL)) FROM DUAL;
SELECT LOCATE('foo', NULL) <=> NULL FROM DUAL;
SELECT LOCATE(NULL, 'o') <=> NULL FROM DUAL;
SELECT LOCATE(NULL, NULL) <=> NULL FROM DUAL;
CREATE TABLE t1 (id int NOT NULL PRIMARY KEY, a varchar(10), p varchar(10));
INSERT INTO t1 VALUES (1, 'foo', 'o');
INSERT INTO t1 VALUES (2, 'foo', NULL);
INSERT INTO t1 VALUES (3, NULL, 'o');
INSERT INTO t1 VALUES (4, NULL, NULL);
SELECT id, LOCATE(a,p) FROM t1;
SELECT id, LOCATE(a,p) IS NULL FROM t1;
SELECT id, ISNULL(LOCATE(a,p)) FROM t1;
SELECT id, LOCATE(a,p) <=> NULL FROM t1;
SELECT id FROM t1 WHERE LOCATE(a,p) IS NULL;
SELECT id FROM t1 WHERE LOCATE(a,p) <=> NULL;
DROP TABLE t1;
--echo End of 5.0 tests --echo End of 5.0 tests

1
sql/item_func.cc
View File

@ -2507,7 +2507,6 @@ longlong Item_func_coercibility::val_int()
void Item_func_locate::fix_length_and_dec() void Item_func_locate::fix_length_and_dec()
{ {
maybe_null= 0;
max_length= MY_INT32_NUM_DECIMAL_DIGITS; max_length= MY_INT32_NUM_DECIMAL_DIGITS;
agg_arg_charsets(cmp_collation, args, 2, MY_COLL_CMP_CONV, 1); agg_arg_charsets(cmp_collation, args, 2, MY_COLL_CMP_CONV, 1);
} }