Commit 89ce81ce authored by unknown's avatar unknown
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Bug #18895: BIT values cause joins to fail 

The Field::eq() considered instances of Field_bit that differ only in 
bit_ptr/bit_ofs equal. This caused equality conditions optimization 
(build_equal_items_for_cond()) to make bad field substitutions that result
in wrong predicates. 
Field_bit requires an overloaded eq() function that checks the bit_ptr/bit_ofs
in addition to Field::eq().


mysql-test/r/select.result:
  Bug #18895: BIT values cause joins to fail
  
  - test case
mysql-test/t/select.test:
  Bug #18895: BIT values cause joins to fail
  
  - test case
sql/field.h:
  Bug #18895: BIT values cause joins to fail
  
  - eq() method overloaded for Field_bit
parent 86334edf

mysql-test/r/select.result

+20 −0
Original line number Diff line number Diff line
@@ -3359,3 +3359,23 @@ id select_type table type possible_keys key key_len ref rows Extra 
1	SIMPLE	t1	range	PRIMARY,b	b	5	NULL	3	Using where

1	SIMPLE	t2	ref	c	c	5	test.t1.a	2	Using where

DROP TABLE t1, t2;

create table t1 (

a int unsigned    not null auto_increment primary key,

b bit             not null,

c bit             not null

);

create table t2 (

a int unsigned    not null auto_increment primary key,

b bit             not null,

c int unsigned    not null,

d varchar(50)

);

insert into t1 (b,c) values (0,1), (0,1);

insert into t2 (b,c) values (0,1);

select t1.a, t1.b + 0, t1.c + 0, t2.a, t2.b + 0, t2.c, t2.d

from t1 left outer join t2 on t1.a = t2.c and t2.b <> 1

where t1.b <> 1 order by t1.a;

a	t1.b + 0	t1.c + 0	a	t2.b + 0	c	d

1	0	1	1	0	1	NULL

2	0	1	NULL	NULL	NULL	NULL

drop table t1,t2;

mysql-test/t/select.test

+26 −0
Original line number Diff line number Diff line
@@ -2840,3 +2840,29 @@ EXPLAIN 
SELECT a, c, d, f FROM t1,t2 WHERE a=c AND b BETWEEN 4 AND 6 AND a > 0;



DROP TABLE t1, t2;



#

# Bug #18895: BIT values cause joins to fail

#

create table t1 (

    a int unsigned    not null auto_increment primary key,

    b bit             not null,

    c bit             not null

);



create table t2 (

    a int unsigned    not null auto_increment primary key,

    b bit             not null,

    c int unsigned    not null,

    d varchar(50)

);



insert into t1 (b,c) values (0,1), (0,1);

insert into t2 (b,c) values (0,1);



-- Row 1 should succeed.  Row 2 should fail.  Both fail.

select t1.a, t1.b + 0, t1.c + 0, t2.a, t2.b + 0, t2.c, t2.d

from t1 left outer join t2 on t1.a = t2.c and t2.b <> 1

where t1.b <> 1 order by t1.a;



drop table t1,t2;

sql/field.h

+8 −1
Original line number Diff line number Diff line
@@ -124,7 +124,7 @@ class Field 
  static bool type_can_have_key_part(enum_field_types);

  static enum_field_types field_type_merge(enum_field_types, enum_field_types);

  static Item_result result_merge_type(enum_field_types);

  bool eq(Field *field)

  virtual bool eq(Field *field)

  {

    return (ptr == field->ptr && null_ptr == field->null_ptr &&

            null_bit == field->null_bit);
@@ -1358,6 +1358,13 @@ class Field_bit :public Field { 
    bit_ptr= bit_ptr_arg;

    bit_ofs= bit_ofs_arg;

  }

  bool eq(Field *field)

  {

    return (Field::eq(field) &&

            field->type() == type() &&

            bit_ptr == ((Field_bit *)field)->bit_ptr &&

            bit_ofs == ((Field_bit *)field)->bit_ofs);

  }

};