SQL QUERY, URGENT PLEASE HELP .....

Question

Hi,
There is a table which stores the sales record, weekly basis.
For example
WEEK______ ITEMNO______SALES______QTY
200201_____10001______10,000______50
200202_____10001______18,000______55
200230_____10001______55,000_____330
Now the report should display the week nos and a Cumulative average.
like
ITEM NO - 10001
WEEKNO____WK-AVG____13WK-AVG____26WK-AVG____52WK-AVG
200201
200202
200203
200230
The WK-AVG is calculated for that perticular (weeks sales /weeks qty) but for 13WK-AVG,26-AVG and 52WK-AVG , The calculationis the (cumulative of last 13 week sales /cumulative of last 13 wk qty)
for example at week 200230 the 13WK-AVG should be
(cumulative sales from week 200218 to 200230 / cumulative qty from week 200218 to 200230 )
the same hold good for 26WK-AVG AND 52WK-AVG. Please suggest me how to do it . This is very urgent . Please help me .
Thanks
Feroz

Answer 1

Feroz,
One way is to use subselects. E.g.,
SELECT WK_AVG, 13WK_AVG, 26WK_AVG, 56WK_AVG FROM
(SELECT (SALES/QTY) AS WK_AVG FROM TABLE WHERE ITEMNO=x AND WEEK = ...),
(SELECT (SUM(SALES)/SUM(QTY)) AS 13WK_AVG WHERE ITEMNO=X AND WEEK > Y AND WEEK <= Z),
hope this helps.
regards,
Stewart