Calculate data of last 30 days on basis of sys date

Question

SELECT DT, ITEMCODE, ITEMNAME, QTY
FROM   TABLE1In above given query, how i could calculate the QTY details of last 30 days, APR, MAY, and JUNE
As the current month is JULY, in AUG, the Qty details are required for last 30 days (from sysdate), MAY, JUNE, JUL
Please suggest.
Yogesh
Edited by: user12957777 on Jul 28, 2010 3:16 AM

Answer 1

Hi,
Use CASE expressions to filter data in particular columns:
SELECT     SUM ( CASE
            WHEN dt >= ADD_MONTHS ( TRUNC (SYSDATE, 'MONTH')
                         , -3
            AND  dt <  ADD_MONTHS ( TRUNC (SYSDATE, 'MONTH')
                         , -2
            THEN qty
           END
         )          AS third_month
,     SUM ( CASE
            WHEN dt >= ADD_MONTHS ( TRUNC (SYSDATE, 'MONTH')
                         , -2
            AND  dt <  ADD_MONTHS ( TRUNC (SYSDATE, 'MONTH')
                         , -1
            THEN qty
           END
         )          AS second_month
,     SUM ( CASE
            WHEN dt >= ADD_MONTHS ( TRUNC (SYSDATE, 'MONTH')
                         , -1
            AND  dt <               TRUNC (SYSDATE, 'MONTH')
            THEN qty
           END
         )          AS last_month
,     SUM ( CASE
            WHEN dt >= TRUNC (SYSDATE) - 30
            AND  dt <  TRUNC (SYSDATE)
            THEN qty
           END
         )          AS last_30_days
FROM     table1
;You can do this with GROUP BY, also, if you want separate rows for each itemname (for example).
I had to guess at some things, such as what you mean by the last 30 days.
If you'd like to post some sample data 9CREATE TABLE and INSERT statements) and the results you want from that data, then I could test this.