I ran across some MySQL weirdness today that bugged me.   Basically the counts for the NULL values are being zeroed out. (or not grouped in the first place)   Does anyone out there have an explanation?

mysql> select distinct value, count(value) from my_table group by value;
+---------------+----------------------+
| value          | count(value)        |
+---------------+----------------------+
|          NULL |                    0 |
|             0 |                  121 |
|             1 |                  321 |
+---------------+----------------------+
3 rows in set (0.02 sec)

mysql> select count(1) from my_table
+----------+
| count(1) |
+----------+
|     4202 |
+----------+
1 row in set (0.00 sec)

Clearly there should be 3,760 NULL values reported, no?

This entry was posted on Tuesday, February 13th, 2007 at 8:52 pm and is filed under programming. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.