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Fixed bug #21698: erroneously a field could be replaced by an

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equal constant under any circumstances.
In fact this substitution can be allowed if the field is
not of a type string or if the field reference serves as 
an argument of a comparison predicate.
This commit is contained in:
igor@rurik.mysql.com
2006-09-07 11:06:37 -07:00
parent ca3229dc1b
commit 34206c6f80
10 changed files with 247 additions and 24 deletions
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35
mysql-test/r/func_str.result
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@@ -1113,4 +1113,39 @@ conv("18383815659218730760",10,10) + 0
select "18383815659218730760" + 0;
"18383815659218730760" + 0
1.8383815659219e+19
CREATE TABLE t1 (code varchar(10));
INSERT INTO t1 VALUES ('a12'), ('A12'), ('a13');
SELECT ASCII(code), code FROM t1 WHERE code='A12';
ASCII(code) code
97 a12
65 A12
SELECT ASCII(code), code FROM t1 WHERE code='A12' AND ASCII(code)=65;
ASCII(code) code
65 A12
INSERT INTO t1 VALUES ('a12 '), ('A12 ');
SELECT LENGTH(code), code FROM t1 WHERE code='A12';
LENGTH(code) code
3 a12
3 A12
4 a12
5 A12
SELECT LENGTH(code), code FROM t1 WHERE code='A12' AND LENGTH(code)=5;
LENGTH(code) code
5 A12
ALTER TABLE t1 ADD INDEX (code);
CREATE TABLE t2 (id varchar(10) PRIMARY KEY);
INSERT INTO t2 VALUES ('a11'), ('a12'), ('a13'), ('a14');
SELECT * FROM t1 INNER JOIN t2 ON t1.code=t2.id
WHERE t2.id='a12' AND (code < 'a00' OR LENGTH(code)=5);
code id
A12 a12
EXPLAIN EXTENDED
SELECT * FROM t1 INNER JOIN t2 ON code=id
WHERE id='a12' AND (code < 'a00' OR LENGTH(code)=5);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref code code 13 const 3 Using where; Using index
1 SIMPLE t2 ref PRIMARY PRIMARY 12 const 1 Using where; Using index
Warnings:
Note 1003 select `test`.`t1`.`code` AS `code`,`test`.`t2`.`id` AS `id` from `test`.`t1` join `test`.`t2` where ((`test`.`t1`.`code` = _latin1'a12') and (`test`.`t2`.`id` = _latin1'a12') and (length(`test`.`t1`.`code`) = 5))
DROP TABLE t1,t2;
End of 5.0 tests