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Fixed bug in LEFT JOIN with impossible ON/WHERE expression

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This commit is contained in:
monty@mashka.mysql.fi
2003-01-19 17:15:14 +02:00
parent 183df2da7f
commit a5e30be0d0
3 changed files with 49 additions and 16 deletions
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13
mysql-test/r/join.result
View File

@ -14,8 +14,7 @@ insert into t1 values (101);
insert into t1 values (105);
insert into t1 values (106);
insert into t1 values (107);
insert into t2 values (107);
insert into t2 values (75);
insert into t2 values (107),(75),(1000);
select t1.id, t2.id from t1, t2 where t2.id = t1.id;
id id
107 107
@ -28,6 +27,16 @@ select t1.id, count(t2.id) from t1,t2 where t2.id = t1.id group by t2.id;
id count(t2.id)
75 1
107 1
select t1.id,t2.id from t2 left join t1 on t1.id>=74 and t1.id<=0 where t2.id=75 and t1.id is null;
id id
NULL 75
explain select t1.id,t2.id from t2 left join t1 on t1.id>=74 and t1.id<=0 where t2.id=75 and t1.id is null;
table type possible_keys key key_len ref rows Extra
t1 const PRIMARY NULL NULL NULL 1 Impossible ON condition
t2 ALL NULL NULL NULL NULL 3 Using where
explain select t1.id, t2.id from t1, t2 where t2.id = t1.id and t1.id <0 and t1.id > 0;
Comment
Impossible WHERE noticed after reading const tables
drop table t1,t2;
CREATE TABLE t1 (
id int(11) NOT NULL auto_increment,

9
mysql-test/t/join.test
View File

@ -19,13 +19,18 @@ insert into t1 values (105);
insert into t1 values (106);
insert into t1 values (107);
insert into t2 values (107);
insert into t2 values (75);
insert into t2 values (107),(75),(1000);
select t1.id, t2.id from t1, t2 where t2.id = t1.id;
select t1.id, count(t2.id) from t1,t2 where t2.id = t1.id group by t1.id;
select t1.id, count(t2.id) from t1,t2 where t2.id = t1.id group by t2.id;
#
# Test problems with impossible ON or WHERE
#
select t1.id,t2.id from t2 left join t1 on t1.id>=74 and t1.id<=0 where t2.id=75 and t1.id is null;
explain select t1.id,t2.id from t2 left join t1 on t1.id>=74 and t1.id<=0 where t2.id=75 and t1.id is null;
explain select t1.id, t2.id from t1, t2 where t2.id = t1.id and t1.id <0 and t1.id > 0;
drop table t1,t2;
#