You can use expression in top clause

SELECT TOP (expression) ...

>Before I make myself completely insane trying to do it, say I have a TestFrameWork table that looks like
>

>Cat     TypeB      TypeC     TypeD     TypeE
>----------------------------------------------------------------
>40          5              3             6            4
>41
>.
>.
>.
>

>
>Where the numbers 5,3, etc are the number of records I need of each Cat and Type and will change periodically but I can't predict what they will be; the 'B','C','D','E' are the difficulty letters (DiffLet). But I need to be able to pull x number of records based on Cat and DiffLet
>
>I know we can say
>

>Select top 5 from (filename) where Cat = '40' and DiffLet = 'B'
>Union
>(Select top 3 from (filename) where Cat = '40' and DiffLet = 'C'
>Union
>...
>
>

>
>but is it possible to say
>

>Select top TestFrameWork.TypeB from (filename) where Cat = '40' and DiffLet = 'B'
>

>?