>>Paul,
>>
>>You're very close. Count simply gives you the number of records it encounters. What you put inside the parenthises may affect the performance but it certainly won't affect the result.
>>
>>Try SUM(IIF(ISNULL(Table1.Rnum) > 0,1,0)) AS RnumTotal.
>>
>
> That almost worked. SUM(IIF(ISNULL(Table1.Rnum),1,0)) AS RnumTotal worked better. Thanks for the help.

Oops, I guess I copied your code and didn't quite modify it enough. Looks like a data-type mismatch waiting to happen!