Average getting calculated incorrectly using group by grouping sets

Question

Hi All
I am using the group by grouping sets to calulate the running totals of aggregate functions like count, sum & avg.
I get the grand totals of count & sum perfectly right but with avg i am getting the averages incorrectly as the number of rows retrieved by the select query increases.
With few rows (3-4) the averages are round about correct but when the number of rows retreived increase say 5 or more than 5 I get absurd average figures
Here is the query I am using
<code>
select AGENT.NAME,
     sum(decode(ACTIVITY.status,'New',1)) cnt,
               sum(decode(ACTIVITY.status,'Open',1)) sumopen ,
     round(avg( decode (ACTIVITY.status,'Open',ACTIVITY.STATUS_DIFF)),0) avgopen,
          sum(decode(ACTIVITY.status,'Sent',1)) sumsent,
     round(avg( decode (ACTIVITY.status,'Sent',ACTIVITY.STATUS_DIFF)),0) avgsent,
               sum(decode(ACTIVITY.status,'Dead',1)) sumdead,
     round(avg( decode (ACTIVITY.status,'Dead',ACTIVITY.STATUS_DIFF)),0) avgdead
               from ACTIVITY, REQUEST , AGENT
               where
               REQUEST.DEALER_NUMBER = AGENT.DEALER_ID
               and REQUEST.CONFIRMATION='Y'
               and REQUEST.REQUEST_ID = ACTIVITY.REQUEST_ID
               and REQUEST.REQUEST_TYPE='B'
               and ACTIVITY.ACTIVITY_DATE between to_date('2006-01-01 ','YYYY-MM-DD') and to_date('2006-08-31','YYYY-MM-DD')
               group by grouping sets((AGENT.DEALER_ID,AGENT.NAME), ())
</code>
Do let me know your suggestions
Regards

Answer 1

Not sure but may be
See below query
SQL> SELECT deptno,ROUND(AVG(sal))
  2  FROM emp
  3  GROUP BY ROLLUP(deptno,sal+rownum);
    DEPTNO ROUND(AVG(SAL))
        10            1300
                      2450
                      5000
                     "2917"      ---Sub total
       20             800
                      1100
                      2975
                      3000
                      3000
                     "2175"      ---Sub total 
      30               950
                      1250
                      1250
                      1500
                      1600
                      2850
                     "1567"    ---Sub total
                     "2073"   ----Grand total
18 rows selected.
Now you want
SQL> SELECT (2917+2175+1567)/3 FROM dual;
(2917+2175+1567)/3
        2219.66667
While it is
SQL> SELECT ROUND(SUM(sal)/COUNT(*)) FROM emp;
ROUND(SUM(SAL)/COUNT(*))
                    2073Khurram