Bug #28157 CHAR(0) displays NULL

• Submitted: 30 Apr 2007 3:44
• Modified: 30 Apr 2007 5:10
• Reporter: Mike Painter
• Status: Can't repeat
• Category: MySQL Server: Data Types
• Severity: S3 (Non-critical)
• Version: 5.0.22
• OS: Any
• CPU Architecture: Any

[30 Apr 2007 3:44] Mike Painter

Description:
CHAR(0) fields, which should be NULL or "" are always displayed as NULL in the query results regardless of their value.

How to repeat:
CREATE TABLE a ( a1 CHAR(0) NULL );
INSERT INTO a VALUES ( "" ), ( NULL );

SELECT a1, a1 IS NULL FROM a;

Current Result:
+------+------------+
| a1   | a1 IS NULL |
+------+------------+
| NULL |          0 |
| NULL |          1 |
+------+------------+

Should Be:
+------+------------+
| a1   | a1 IS NULL |
+------+------------+
|      |          0 |
| NULL |          1 |
+------+------------+

Suggested fix:
Make CHAR(0) fields with a value of "" return "" instead of NULL

[30 Apr 2007 5:10] Valeriy Kravchuk

Please, use newer version, 5.0.37. It works exactly as you expected there.