Case Statement problem

Question

Hi All,
I am trying to come up with a case statement for the below provided sql but i am not able to do that can you guys help me out
(SELECT NO_OF_DAYS.id_person
FROM NO_OF_DAYS
WHERE NO_OF_DAYS.STATUS = 'Y'
AND NO_OF_DAYS.ID_PERSON = PERSON.ID_PERSON
HAVING (SUM( NO_OF_DAYS.DT_STAT_END
- NO_OF_DAYS.DT_STAT_START)) > 180)
the case statement i am trying to come up with is if the person status start - end date is greater than 180 days then 'y' else 'n' end

Answer 1

Hi.
If you have two tables: NO_OF_DAYS and PERSON and PERSON is a parent table of NO_OF_DAYS this could work:
WITH NO_OF_DAYS AS
     SELECT 1 id_person,TO_DATE('2012-01-01','YYYY-MM-DD') DT_STAT_START, TO_DATE('2012-01-31','YYYY-MM-DD') DT_STAT_END,'Y' status FROM dual UNION
     SELECT 1 id_person,TO_DATE('2012-02-01','YYYY-MM-DD') DT_STAT_START, TO_DATE('2012-02-20','YYYY-MM-DD') DT_STAT_END,'Y' status FROM dual UNION
     SELECT 2 id_person,TO_DATE('2012-01-01','YYYY-MM-DD') DT_STAT_START, TO_DATE('2012-03-31','YYYY-MM-DD') DT_STAT_END,'Y' status FROM dual UNION
     SELECT 2 id_person,TO_DATE('2012-04-01','YYYY-MM-DD') DT_STAT_START, TO_DATE('2012-10-01','YYYY-MM-DD') DT_STAT_END,'Y' status FROM dual
PERSON AS
     SELECT 1 id_person FROM DUAL UNION
     SELECT 2 id_person FROM DUAL
SELECT
     NO_OF_DAYS.id_person,
     CASE WHEN (SUM(NO_OF_DAYS.DT_STAT_END- NO_OF_DAYS.DT_STAT_START)) > 180 THEN 'Y'
          ELSE 'N'
     END y_n
FROM
     NO_OF_DAYS,
     PERSON
WHERE
     NO_OF_DAYS.ID_PERSON = PERSON.ID_PERSON AND
     NO_OF_DAYS.STATUS = 'Y'
GROUP BY NO_OF_DAYS.id_person;
--results
ID_PERSON     Y_N
1          N
2          YHope this helps.
Regards.