Why use COUNT(*) in MySQL? Why not use COUNT(column)?

Try this test yourself:


$ mysql -u root test
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 660 to server version: 4.0.11a-gamma

Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

mysql> create table nulls_baby (c char);
Query OK, 0 rows affected (0.01 sec)

mysql> insert into nulls_baby values (NULL);
Query OK, 1 row affected (0.00 sec)

mysql> select count(c), count(*) from nulls_baby;
+----------+----------+
| count(c) | count(*) |
+----------+----------+
|        0 |        1 |
+----------+----------+
1 row in set (0.00 sec)


Now, you *probably* shouldn't be using NULL values in the first place,
but just to be on the safe side, it is good practice to use COUNT(*).

that is all