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Bug #21159: Optimizer: wrong result after AND with different data types

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Disable const propagation for Item_hex_string.
This must be done because Item_hex_string->val_int() is not
the same as (Item_hex_string->val_str() in BINARY column)->val_int().
We cannot simply disable the replacement in a particular context (
e.g. <bin_col> = <int_col> AND <bin_col> = <hex_string>) since
Items don't know the context they are in and there are functions like 
IF (<hex_string>, 'yes', 'no').
Note that this will disable some valid cases as well 
(e.g. : <bin_col> = <hex_string> AND <bin_col2> = <bin_col>) but 
there's no way to distinguish the valid cases without having the
Item's parent say something like : Item->set_context(Item::STRING_RESULT)
and have all the Items that contain other Items do that consistently.
This commit is contained in:
gkodinov/kgeorge@macbook.gmz
2006-08-15 10:13:17 +03:00
parent 83896aa8f6
commit c606c63f0e
3 changed files with 32 additions and 1 deletions
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7
mysql-test/r/compare.result
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@ -42,3 +42,10 @@ CHAR(31) = '' '' = CHAR(31)
SELECT CHAR(30) = '', '' = CHAR(30);
CHAR(30) = '' '' = CHAR(30)
0 0
create table t1 (a tinyint(1),b binary(1));
insert into t1 values (0x01,0x01);
select * from t1 where a=b;
a b
select * from t1 where a=b and b=0x01;
a b
drop table if exists t1;