Commit 54f3949a authored by igor@olga.mysql.com's avatar igor@olga.mysql.com
Browse files

Fixed bug #29611. 

If a primary key is defined over column c of enum type then 
the EXPLAIN command for a look-up query of the form
  SELECT * FROM t WHERE c=0
said that the query was with an impossible where condition though the
query correctly returned non-empty result set when the table indeed 
contained rows with error empty strings for column c. 

This kind of misbehavior was due to a bug in the function 
Field_enum::store(longlong,bool) that erroneously returned 1 if
the the value to be stored was equal to 0. 
Note that the method 
Field_enum::store(const char *from,uint length,CHARSET_INFO *cs)
correctly returned 0 if a value of the error empty string 
was stored.
parent 7402fd6e

mysql-test/r/type_enum.result

+24 −0
Original line number Diff line number Diff line
@@ -1829,3 +1829,27 @@ c1 + 0 
0

2

DROP TABLE t1,t2;

CREATE TABLE t1(a enum('a','b','c','d'));

INSERT INTO t1 VALUES (4),(1),(0),(3);

Warnings:

Warning	1265	Data truncated for column 'a' at row 3

SELECT a FROM t1;

a

d

a



c

EXPLAIN SELECT a FROM t1 WHERE a=0;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	Using where

SELECT a FROM t1 WHERE a=0;

a



ALTER TABLE t1 ADD PRIMARY KEY (a);

EXPLAIN SELECT a FROM t1 WHERE a=0;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t1	const	PRIMARY	PRIMARY	1	const	1	Using index

SELECT a FROM t1 WHERE a=0;

a



DROP TABLE t1;

mysql-test/t/type_enum.test

+24 −0
Original line number Diff line number Diff line
@@ -200,3 +200,27 @@ CREATE TABLE t2 SELECT * FROM t1; 
SELECT c1 + 0 FROM t2;



DROP TABLE t1,t2;



#

# Bug#29661: Lookup by 0 for a primary index over a enum type  

#



CREATE TABLE t1(a enum('a','b','c','d'));

INSERT INTO t1 VALUES (4),(1),(0),(3);



SELECT a FROM t1;



EXPLAIN SELECT a FROM t1 WHERE a=0;

SELECT a FROM t1 WHERE a=0;



ALTER TABLE t1 ADD PRIMARY KEY (a);



EXPLAIN SELECT a FROM t1 WHERE a=0;

SELECT a FROM t1 WHERE a=0;



DROP TABLE t1;

sql/field.cc

+5 −2
Original line number Diff line number Diff line
@@ -7640,9 +7640,12 @@ int Field_enum::store(longlong nr, bool unsigned_val) 
  if ((ulonglong) nr > typelib->count || nr == 0)

  {

    set_warning(MYSQL_ERROR::WARN_LEVEL_WARN, WARN_DATA_TRUNCATED, 1);

    if (nr != 0 || table->in_use->count_cuted_fields)

    {

      nr= 0;

      error= 1;

    }

  }

  store_type((ulonglong) (uint) nr);

  return error;

}