Question

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

This may return row, where User is null but count is some number. How can I modify query so instead of empty(null) row I can see some string?

Answer 1

Normally, I’d suggest coalesce to automatically morph null values to something else, but it appears MsAccess may not have this. You could try nz instead:

select     nz(user, '<<NULL>>') as user,
           count(*) as count
from       tests
group by   user

instead.

You may also find that it’s more efficient (this depends on your DBMS of course) to get rid of per-row functions altogether and union two separate queries, something like:

select user as user, count(*) as count
    from tests
    where user is not null
    group by user
union all select '<<NULL>>' as user, count(*) as count
    from tests
    where user is null

But whether MsAccess allows this (or whether you care), I don’t know. I know it will most likely perform better on the main DBMS I use but you should always remember: measure, don’t guess!