A little more definition would be helpful but here's a shot in the dark.
Try braking the query into two subqueries, like:

select pat_id,max(vis_date) as lastvisit from sometable group by 1 into cursor temp
select somefields from anothertable where pat_id in (select pat_id from temp)

If you post your tables structures and the SQL syntax that isn't working, I may be able to provide a more helpful answer.

Good Luck.

>Does anyone know how I can implement IIF statements in an SQL. I am running a SQL select statement that looks for the patient id but the problem arises when the patient has two different visit dates to the doctor. but I only need the latest date.
>
>Jeff T.