Query Problem

I am trying retrieve all records in a table by the max presciption by group of territory.

In my table I have columns-- IMS_num, last_name, terriorty_num, pres_num

I want to see all the data by territory and max pres_num
I am lost.

I got this far..

select max(pres_num) from table group by territory_num.

I do not know how to get the last_name and territory_num displayed.Perhaps it'll help ...

SELECT territory_num, last_name, max(pres_num)
FROM your_table
GROUP BY territory_num, last_name;