Try this. I have assumed that birthdate is stored as datetime. If it is a varchar, then be careful to check for differences in regional dates ( 1/2/1989 and 2/1/1989...

Jules,

I had a similar problem and dealt with it using the code below. If there is a better way to do it though I would also be interested to see...

try this

declare @sqlstring nvarchar(4000)

set @sqlstring = 'select top ' + cast(@topnproduct as varchar) + ' * from table'

exec(@sqlstring)