Bug #19833 Incorect display of NULL results in Command Line Client

• Submitted: 15 May 2006 23:09
• Modified: 15 May 2006 23:20
• Reporter: Martin Krsek
• Status: Duplicate
• Category: MySQL Server
• Severity: S3 (Non-critical)
• Version: 5.0.20-nt
• OS: Windows (Win2k)
• CPU Architecture: Any

[15 May 2006 23:09] Martin Krsek

Description:
Result with value NULL is displayed incorrectly as empty string:

mysql> select concat_ws(NULL, NULL);
+-----------------------+
| concat_ws(NULL, NULL) |
+-----------------------+
|                       |
+-----------------------+

but result is really NULL:

mysql> select ISNULL(concat_ws(NULL, NULL));
+-------------------------------+
| ISNULL(concat_ws(NULL, NULL)) |
+-------------------------------+
| 1                             |
+-------------------------------+

but:

mysql> select NULL * NULL;
+-------------+
| NULL * NULL |
+-------------+
| NULL        |
+-------------+

(in 4.1.11-Debian_4sarge2 it works fine:
mysql> select concat_ws(NULL, NULL);
+-----------------------+
| concat_ws(NULL, NULL) |
+-----------------------+
| NULL                  |
+-----------------------+
)

How to repeat:
select concat_ws(NULL, NULL);

Suggested fix:
mysql> select concat_ws(NULL, NULL);
+-----------------------+
| concat_ws(NULL, NULL) |
+-----------------------+
|   NULL                    |
+-----------------------+

[15 May 2006 23:20] Martin Krsek

Sorry, duplicate for MySQL Bugs: #19228: mysql client: don't print NULL.