Full outer join with "case when" and subquery - sql

Question

I have a full outer join query with case when and sub query in oracle. What I am trying to accomplish is aggregating current year data and previous year data from the same table in order to compare them. However my FULL OUTER JOIN is acting as an inner join not returning the null values from both the current year and the previous year.
Here is my code:
SELECT
SQ1.CHANNEL,
SQ1.SHORT,
SQ1.NAME,
SQ1.RDC,
SQ1.CY_APPROVED_COUNT,
SQ2.PY_APPROVED_COUNT,
SQ1.CY_APPROVED_VOLUME,
SQ2.PY_APPROVED_VOLUME,
SQ1.CY_DECLINED_COUNT,
SQ2.PY_DECLINED_COUNT,
SQ1.CY_DECLINED_VOLUME,
SQ2.PY_DECLINED_VOLUME,
SQ1.CY_RETURNED_COUNT,
SQ2.PY_RETURNED_COUNT,
SQ1.CY_RETURNED_VOLUME,
SQ2.PY_RETURNED_VOLUME
FROM ( SELECT
CHANNEL,
SHORT,
NAME,
RDC,
SUM (CASE WHEN STATUS = 'Approved' THEN APP_COUNTS ELSE 0 END) AS CY_APPROVED_COUNT,
SUM (CASE WHEN STATUS = 'Approved' THEN PROJ_VOL ELSE 0 END) AS CY_APPROVED_VOLUME,
SUM (CASE WHEN STATUS = 'Declined' THEN APP_COUNTS ELSE 0 END) AS CY_DECLINED_COUNT,
SUM (CASE WHEN STATUS = 'Declined' THEN PROJ_VOL ELSE 0 END) AS CY_DECLINED_VOLUME,
SUM (CASE WHEN STATUS = 'Returned' THEN APP_COUNTS ELSE 0 END) AS CY_RETURNED_COUNT,
SUM (CASE WHEN STATUS = 'Returned' THEN PROJ_VOL ELSE 0 END) AS CY_RETURNED_VOLUME
FROM WFRT_MSP_SP_MTD
WHERE PERIOD >= TO_DATE('2016/02/01', 'yyyy/mm/dd')
AND PERIOD <= TO_DATE('2016/02/13','yyyy/mm/dd')
AND CHANNEL = 'MSP'
AND RDC = 'BASE'
GROUP BY
CHANNEL,
SHORT,
NAME,
RDC
) SQ1
-- NOT CORRECTLY SHOWING NULL VALUES
FULL OUTER JOIN
( SELECT
CHANNEL,
SHORT,
NAME,
RDC,
SUM (CASE WHEN STATUS = 'Approved' THEN APP_COUNTS ELSE 0 END) AS PY_APPROVED_COUNT,
SUM (CASE WHEN STATUS = 'Approved' THEN PROJ_VOL ELSE 0 END) AS PY_APPROVED_VOLUME,
SUM (CASE WHEN STATUS = 'Declined' THEN APP_COUNTS ELSE 0 END) AS PY_DECLINED_COUNT,
SUM (CASE WHEN STATUS = 'Declined' THEN PROJ_VOL ELSE 0 END) AS PY_DECLINED_VOLUME,
SUM (CASE WHEN STATUS = 'Returned' THEN APP_COUNTS ELSE 0 END) AS PY_RETURNED_COUNT,
SUM (CASE WHEN STATUS = 'Returned' THEN PROJ_VOL ELSE 0 END) AS PY_RETURNED_VOLUME
FROM WFRT_MSP_SP_MTD
WHERE PERIOD >= TO_DATE('2015/02/01', 'yyyy/mm/dd')
AND PERIOD <= TO_DATE('2015/02/13','yyyy/mm/dd')
AND CHANNEL = 'MSP'
AND RDC = 'BASE'
GROUP BY
CHANNEL,
SHORT,
NAME,
RDC
) SQ2
ON sq1.short = sq2.short
;
Please help if you can.

Answer 1

Just use conditional aggregation:
SELECT CHANNEL, SHORT, NAME, RDC,
SUM(CASE WHEN this_year = 1 AND STATUS = 'Approved' THEN APP_COUNTS ELSE 0 END) AS CY_APPROVED_COUNT,
SUM(CASE WHEN this_year = 1 AND STATUS = 'Approved' THEN PROJ_VOL ELSE 0 END) AS cY_APPROVED_VOLUME,
SUM(CASE WHEN this_year = 1 AND STATUS = 'Declined' THEN APP_COUNTS ELSE 0 END) AS CY_DECLINED_COUNT,
SUM(CASE WHEN this_year = 1 AND STATUS = 'Declined' THEN PROJ_VOL ELSE 0 END) AS CY_DECLINED_VOLUME,
SUM(CASE WHEN this_year = 1 AND STATUS = 'Returned' THEN APP_COUNTS ELSE 0 END) AS CY_RETURNED_COUNT,
SUM(CASE WHEN this_year = 1 AND STATUS = 'Returned' THEN PROJ_VOL ELSE 0 END) AS CY_RETURNED_VOLUME,
SUM(CASE WHEN prev_year = 1 AND STATUS = 'Approved' THEN APP_COUNTS ELSE 0 END) AS PY_APPROVED_COUNT,
SUM(CASE WHEN prev_year = 1 AND STATUS = 'Approved' THEN PROJ_VOL ELSE 0 END) AS PY_APPROVED_VOLUME,
SUM(CASE WHEN prev_year = 1 AND STATUS = 'Declined' THEN APP_COUNTS ELSE 0 END) AS PY_DECLINED_COUNT,
SUM(CASE WHEN prev_year = 1 AND STATUS = 'Declined' THEN PROJ_VOL ELSE 0 END) AS PY_DECLINED_VOLUME,
SUM(CASE WHEN prev_year = 1 AND STATUS = 'Returned' THEN APP_COUNTS ELSE 0 END) AS PY_RETURNED_COUNT,
SUM(CASE WHEN prev_year = 1 AND STATUS = 'Returned' THEN PROJ_VOL ELSE 0 END) AS PY_RETURNED_VOLUME
FROM (SELECT msm.*,
(CASE WHEN PERIOD >= DATE '2015-02-01' AND
PERIOD <= '2015-02-13'
THEN 1 ELSE 0
END) as prev_year,
(CASE WHEN PERIOD >= DATE '2016-02-01' AND
PERIOD <= '2016-02-13'
THEN 1 ELSE 0
END) as this_year
FROM WFRT_MSP_SP_MTD msm
) msm
WHERE CHANNEL = 'MSP' AND RDC = 'BASE'
GROUP BY CHANNEL, SHORT, NAME, RDC;