What is wrong with this query?

[Quoted] [Quoted] I wonder why am I getting a not a single-group group function error with this query:

[Quoted] [Quoted] SELECT distinct owner_id ||' ' as "Owner ID", Count(distinct owner_id) as "Purch. Count", Sum(price) as "Purch. Count",

       avg(price) as "Avg. Purch."
FROM purchase_tbl
[Quoted] WHERE purchase_date BETWEEN

       TO_DATE('01-01-1998', 'mm-dd-yyyy') and
       TO_DATE('12-31-2000', 'mm-dd-yyyy') 

Do I have to use a nested query, and if yes, which column should I use for the inner query? Received on Tue Feb 12 2002 - 12:02:01 CET