Question

SELECT User, COUNT(User) as count FROM Tests GROUP by User;

This works. However, if some User rows contains null values I get the following:

User    count
        0
u1      5
u2      3
u3      9

As you can see, the null value rows shows 0 count, however, it’s not really zero.

SELECT * FROM Tests WHERE IsNull(User) shows non zero actual value.
This makes me thing that I should change my original query so null User will be counted correctly.

Answer 1

Use COUNT(*) instead:

  SELECT User, COUNT(*) AS count 
    FROM Tests 
GROUP BY User;

From documentation:

SYNTAX
Count(expr)

The Count function does not count
records that have Null fields unless
expr is the asterisk (*) wildcard
character . If you use an asterisk,
Count calculates the total number of
records, including those that contain
Null fields. Count(*) is considerably
faster than Count([Column Name]).