[MDEV-9333] Inconsistency when copying from INT to ENUM Created: 2015-12-28  Updated: 2019-11-18

Status: Open
Project: MariaDB Server
Component/s: OTHER
Affects Version/s: 5.5, 10.0, 10.1, 10.2
Fix Version/s: 10.2

Type: Bug Priority: Minor
Reporter: Alexander Barkov Assignee: Alexander Barkov
Resolution: Unresolved Votes: 0
Labels: None

Epic Link: Data type cleanups

 Description   

In this script:

DROP TABLE IF EXISTS t1;
 
CREATE TABLE t1 (a INT, b ENUM('2','3'));
 
INSERT INTO t1 VALUES(2,'2');
 
UPDATE t1 SET b=a;
 
SELECT b FROM t1;

copying is done using val_int() method of the field "a", which returns 2 and then further converts to ENUM value[2], which is '3'. So the script returns:

+------+
 
| b    |
 
+------+
 
| 3    |
 
+------+

The same behavior is demonstrated in this script:

DROP TABLE IF EXISTS t1,t2;
 
CREATE TABLE t1 (a INT);
 
INSERT INTO t1 VALUES (2);
 
CREATE TABLE t2 (b ENUM('2','3'));
 
INSERT INTO t2 SELECT * FROM t1;
 
SELECT *FROM t2;
 

+------+
 
| b    |
 
+------+
 
| 3    |
 
+------+

Now if I use ALTER:

DROP TABLE IF EXISTS t1;
 
CREATE TABLE t1 (a INT);
 
INSERT INTO t1 VALUES(2);
 
ALTER TABLE t1 CHANGE a b ENUM('2','3');
 
SELECT * FROM t1;

it goes through val_str() of the field "a" which returns string '2', so the result is:

+------+
 
| b    |
 
+------+
 
| 2    |
 
+------+

All three cases should return the same result.

 Comments   
Comment by Brian Evans [ 2016-05-20 ]

I see a regression in the treatment of enums and ints in general here.

create table mariadb_bug ( i int primary key, bug enum('0','1') NOT NULL DEFAULT '0' );
insert into mariadb_bug values (1, 0),(2, 0),(3, 1);
select * from mariadb_bug;

MySQL 5.1.50:
 
+---+-----+
 
| i | bug |
 
+---+-----+
 
| 1 | 0   |
 
| 2 | 0   |
 
| 3 | 1   |
 
+---+-----+
 
 
 
MariaDB 10.0.23:
 
+---+-----+
 
| i | bug |
 
+---+-----+
 
| 1 |     |
 
| 2 |     |
 
| 3 | 0   |
 
+---+-----+
 
 
 
MariaDB 10.1.14:
 
+---+-----+
 
| i | bug |
 
+---+-----+
 
| 1 |     |
 
| 2 |     |
 
| 3 | 0   |
 
+---+-----+

Comment by Brian Evans [ 2016-05-20 ]

Interestingly enough:

MySQL 5.5.48:

+---+-----+
 
| i | bug |
 
+---+-----+
 
| 1 |     |
 
| 2 |     |
 
| 3 | 0   |
 
+---+-----+

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