Alternate to Not IN

Question

Hello,
I am using the following query to display count of unapproved transactions.
SELECT GH_TXN_CODE , COUNT(*)TOTAL
FROM OT_GR_HEAD
WHERE GH_APPR_UID IS NULL
AND GH_TXN_CODE NOT IN ('S_SIF','S_SIE')
GROUP BY GH_TXN_CODE
UNION
SELECT PH_TXN_CODE, COUNT(*)
FROM OT_PO_HEAD
WHERE PH_APPR_UID IS NULL
AND PH_TXN_CODE NOT IN ('S_PIE', 'S_PIO')
GROUP BY PH_TXN_CODE
It is taking nearly three minutes to execute the query.
Please suggest alternate to NOT IN to impore performance.
Regards
Krishna

Answer 1

SELECT GH_TXN_CODE,sum(decode(PH_TXN_CODE,'S_SIF',0,'S_SIE',0,1)) TOTAL FROM OT_GR_HEAD WHERE GH_APPR_UID IS NULL
--AND GH_TXN_CODE NOT IN ('S_SIF','S_SIE')
GROUP BY GH_TXN_CODE
having sum(decode(PH_TXN_CODE,'S_SIF',0,'S_SIE',0,1)) > 0 --added by me
UNION
SELECT PH_TXN_CODE,sum(decode(PH_TXN_CODE,'S_PIE',0,'S_PIO',0,1)) FROM OT_PO_HEAD WHERE PH_APPR_UID IS NULL
--AND PH_TXN_CODE NOT IN ('S_PIE', 'S_PIO')
GROUP BY PH_TXN_CODE
having sum(decode(PH_TXN_CODE,'S_PIE',0,'S_PIO',0,1)) > 0 --added
try this,
Cheers,
Sivarama