how to use case with group by? - sql

Question

the query works well but when iam adding group by it gives me [Error] ORA-01427 here is the main query
SELECT DISTINCT Contract_number,
area_number,
area_name,
ADVANCE_PAY,
Postponed_Amount,
extract_number,
total
FROM (SELECT xxr.Contract_num Contract_number,
xxr.p_area_no area_number,
xxr.p_area_name area_name,
xxr.ADVANCE_PAY ADVANCE_PAY,
xxr.DEFERRED_BOOST Postponed_Amount,
xxr.release_num extract_number,
and here is the case statement :
(SELECT DISTINCT
CASE
WHEN :p_item_code IS NOT NULL
THEN
TOTAL_AMOUNT
WHEN :p_item_code IS NULL
THEN
( (SELECT NVL (SUM (TOTAL_AMOUNT), 0)
FROM XXEXTRACT.XXNATGAS_REALSES_LINES
WHERE XXEXTRACT.XXNATGAS_REALSES.release_id =
XXEXTRACT.XXNATGAS_REALSES_LINES.release_id))
ELSE
NULL
END
FROM XXEXTRACT.XXNATGAS_REALSES_LINES xxrl,
XXEXTRACT.XXNATGAS_REALSES
WHERE 1 = 1
AND xxrl.release_id =
XXEXTRACT.XXNATGAS_REALSES.release_id)
AS total
and here is the from part :
FROM XXEXTRACT.XXNATGAS_REALSES_LINES xxrl,
XXEXTRACT.XXNATGAS_REALSES xxr
WHERE 1 = 1
AND xxrl.release_id = xxr.release_id
AND xxr.release_date >= NVL (:p_date_from, xxr.release_date)
AND xxr.release_date <= NVL (:p_date_to, xxr.release_date)
AND xxr.Contract_num = NVL (:p_cont_num, xxr.Contract_num)
AND xxr.vendor_id = NVL (:p_ven_id, xxr.vendor_id)
AND xxr.vendor_site_id = NVL (:p_site_id, xxr.vendor_site_id)
)
and here is the group by :
GROUP BY Contract_number,
area_number,
area_name,
ADVANCE_PAY,
Postponed_Amount,
extract_number,
total;
these is the full query so please any help

Answer 1

For sure I couldn't understand very well your query. You could improve your post for next time.
As answer, I think you should encapsulate your select statment and group by using your select as subquery. It is not the best approach but it may works fine.
select *
from (
select distinct Contract_number
,area_number
,area_name
,ADVANCE_PAY
,Postponed_Amount
,extract_number
,total
from (
select xxr.Contract_num Contract_number
,xxr.p_area_no area_number
,xxr.p_area_name area_name
,xxr.ADVANCE_PAY ADVANCE_PAY
,xxr.DEFERRED_BOOST Postponed_Amount
,xxr.release_num extract_number
,(
select distinct case
when :p_item_code is not null
then TOTAL_AMOUNT
when :p_item_code is null
then (
(
select NVL(SUM(TOTAL_AMOUNT), 0)
from XXEXTRACT.XXNATGAS_REALSES_LINES
where XXEXTRACT.XXNATGAS_REALSES.release_id = XXEXTRACT.XXNATGAS_REALSES_LINES.release_id
)
)
else null
end
from XXEXTRACT.XXNATGAS_REALSES_LINES xxrl
,XXEXTRACT.XXNATGAS_REALSES
where 1 = 1
and xxrl.release_id = XXEXTRACT.XXNATGAS_REALSES.release_id
) as total
from XXEXTRACT.XXNATGAS_REALSES_LINES xxrl
,XXEXTRACT.XXNATGAS_REALSES xxr
where 1 = 1
and xxrl.release_id = xxr.release_id
and xxr.release_date >= NVL(:p_date_from, xxr.release_date)
and xxr.release_date <= NVL(:p_date_to, xxr.release_date)
and xxr.Contract_num = NVL(:p_cont_num, xxr.Contract_num)
and xxr.vendor_id = NVL(:p_ven_id, xxr.vendor_id)
and xxr.vendor_site_id = NVL(:p_site_id, xxr.vendor_site_id)
)
) TBL1
group by TBL1.Contract_number
,TBL1.area_number
,TBL1.area_name
,TBL1.ADVANCE_PAY
,TBL1.Postponed_Amount
,TBL1.extract_number
,TBL1.total;