Update SQL with CASE and SUM functions - sql

Question

I know this seems like a similar question that has been answered before, and it may be. However, I have looked through the answers and they seem to all work along the table.x = sum (case when (x))) example. None of them seem to work with getting a sum inside the CASE function.
My script before attempting to create an update script is
SELECT
Item
,Loc
,MinDRPQty
,NetNeed
,CASE
WHEN (NetNeed/MinDRPQty) <= 1 THEN MinDRPQty --use existing multiplier if sum is less than multiplier
ELSE CEIL(NetNeed/MinDRPQty)*MinDRPQty --determine appropriate multiple, convert to int, and multiply
END as "ExpectedOrder"
FROM
(
select
s.Item as Item,
s.Loc as Loc,
p.MinDRPQty as MinDRPQty,
SUM (s.OH + s.UDC_ActualIT + s.UDC_CommitIT - s.UDC_AllCustOrd - s.UDC_ADJ_AvgDailyDmd* (p.DRPCovDur/1440) - s.UDC_SafetyStock) as NetNeed
from SKU s, SKUPlanningParam p
where s.Item = p.Item and s.Loc = p.Loc group by s.Item, s.Loc, p.MinDRPQty
)
I am looking to update a field called UDC_NetNeed. So I need the NetNeed from this statement. Any help would be greatly appreciated. If this has been answered before, and I have missed it, I apologize.

Answer 1

update SKU s
set UDC_NetNeed = (
SELECT
CASE
WHEN (NetNeed/nullif(MinDRPQty, 0)) <= 1 THEN MinDRPQty --use existing multiplier if sum is less than multiplier
ELSE CEIL(NetNeed/nullif(MinDRPQty, 0))*MinDRPQty --determine appropriate multiple, convert to int, and multiply
END
FROM
(
select
s.Item as Item,
s.Loc as Loc,
p.MinDRPQty as MinDRPQty,
SUM (s.OH + s.UDC_ActualIT + s.UDC_CommitIT - s.UDC_AllCustOrd - s.UDC_ADJ_AvgDailyDmd* (p.DRPCovDur/1440) - s.UDC_SafetyStock) as NetNeed
from SKU s, SKUPlanningParam p
where s.Item = p.Item and s.Loc = p.Loc group by s.Item, s.Loc, p.MinDRPQty
) a where a.Item = s.Item and a.Loc = s.Loc and ROWNUM = 1
);
It's not clear what you what to update, I suppose it's the SKU table
" and ROWNUM = 1" this condition is unclear and added in order to prevent multiple results in the correlated subquery.
Some info
select
s.Item as Item,
s.Loc as Loc,
p.MinDRPQty as MinDRPQty,
SUM (...)
...
group by s.Item, s.Loc, p.MinDRPQty
It means that result can be something like this
Row 1: item=1, loc=1, MinDRPQty=1, netNeed=100500
Row 2: item=1, loc=1, MinDRPQty=2, netNeed=500
Suppose there is one row with item=1, loc=1 in the table SKU.
When you make the update described above there is a problem: for row "item=1, loc=1" Oracle does't know which netNeed to choose (100500 or 500). That's why I put "and ROWNUM = 1" (any first row that was found). But I'm not sure if it makes sense in your case. Maybe you need some extra condition here!