12 months AGO date

Question

i have a ccan_dt(connection cancellation date) for every agent
i am trying to calculate the amount the agents spend before 12 months of connection cancellation date ie ccan_dt
agent ccandt
a 14/8/2009
b 12/7/2003
c 08/10/2000
d 7/8/1999
select sum(spend),agent from spendmas where spenddt between d1 and d2 group by agent
in the above d2 is the ccan_dt of each agent and d1 is 12 before date of d2
can any one suggest the efficinet way of acheving this.
i did this by creating a temp table to hold the dates and then calculated the spend.
but how can i achevie this with out creating a temp table.
is there any regular expression which can get 12 months ago date as in OBIEE.
please advice..

Answer 1

user633377 wrote:
select sum(spend),agent from spendmas where spenddt between d1 and d2 group by agent
in the above d2 is the ccan_dt of each agent and d1 is 12 before date of d2
can any one suggest the efficinet way of acheving this.
i did this by creating a temp table to hold the dates and then calculated the spend.
but how can i achevie this with out creating a temp table.
is there any regular expression which can get 12 months ago date as in OBIEE.
please advice..Didn't quiet understand the need for a temp table.
However you can get a date from 12 months before by using ADD_MONTHS Function.
Something like:
SQL> SELECT SYSDATE FROM Dual
  2  /
SYSDATE
20-AUG-09
1 row selected.
SQL> SELECT ADD_MONTHS(sysdate, -12) FROM Dual
  2  /
ADD_MONTH
20-AUG-08
1 row selected.
SQL>So your query might be changed to
  SELECT   SUM (spend), agent
    FROM   spendmas
   WHERE   spenddt BETWEEN d2 AND ADD_MONTHS (d2, -12)
GROUP BY   agentAssumed d2 is cancellation date
Hope this helps.
Regards,
Jo