in a logic loop!

I have a logic problem: I have a complicated query. The main thing is that I have an ID, and for a particular ID, I may have between 1 to 3 rows returned. The rows returned are variable, that is for 1 particular ID there might just be 1 row and at a later time it may have 3 rows. But what I need to do is print only one row for a particular ID. Please do not suggest I do it through SQL itself, because it's after using various aggregate functions that I have arrived at the min. result set. I need the logic clarified, because it has me stumped. It will be simple for a clear-thinking individual. What I am doing is: I maintain a set of details in say $prev_row (previous row) and another in cur_row (current row). The minute my cur_row detail (one unique id) doesn't match the prev_row detail, I print out all the previous row details, and reinitialize the various variables (all in a loop). This works fine for all cases but fails for the last ID, because of the logic used. Do I need to create a special case for the last one, or can anyone suggest a better way? -Thanks Naintara