Commit d14a27fd authored by unknown's avatar unknown
Browse files

bug#4816. index search for NULL in blob

parent 9ca47d04

myisam/mi_key.c

+2 −0
Original line number Diff line number Diff line
@@ -177,6 +177,8 @@ uint _mi_pack_key(register MI_INFO *info, uint keynr, uchar *key, uchar *old, 
      if (!(*key++= (char) 1-*old++))			/* Copy null marker */

      {

	k_length-=length;

        if (keyseg->flag & (HA_VAR_LENGTH | HA_BLOB_PART))

          k_length-=2;                                  /* Skip length */

	continue;					/* Found NULL */

      }

    }

mysql-test/r/myisam.result

+9 −0
Original line number Diff line number Diff line
@@ -453,3 +453,12 @@ table type possible_keys key key_len ref rows Extra 
t1	system	NULL	NULL	NULL	NULL	1	Using temporary

t2	index	NULL	PRIMARY	4	NULL	2	Using index; Distinct

drop table t1,t2;

create table t1 ( a tinytext, b char(1), index idx (a(1),b) );

insert into t1 values (null,''), (null,'');

explain select count(*) from t1 where a is null;

table	type	possible_keys	key	key_len	ref	rows	Extra

t1	ref	idx	idx	4	const	1	Using where

select count(*) from t1 where a is null;

count(*)

2

drop table t1;

mysql-test/t/myisam.test

+10 −0
Original line number Diff line number Diff line
@@ -436,3 +436,13 @@ select sql_big_result distinct t1.a from t1,t2; 
explain select sql_big_result distinct t1.a from t1,t2 order by t2.a;

explain select distinct t1.a from t1,t2 order by t2.a;

drop table t1,t2;



#

# index search for NULL in blob. Bug #4816

#

create table t1 ( a tinytext, b char(1), index idx (a(1),b) );

insert into t1 values (null,''), (null,'');

explain select count(*) from t1 where a is null;

select count(*) from t1 where a is null;

drop table t1;