Query where sum of a group of records greater than ZERO

Question

I am trying to write a query on a trades table where there are buy and sell transactions for various items. Trying to build a query where on a given date I wish to know how many of each item do I hold. That part is achieved.

Now the issue is, the query I have written returns a list of items which were once bought, and sold already, so on a given date that item shows 0 as balance. I want to avoid all items with zero balance as of that particular date.

My query looks like this.

Select 
    I.itemName, I.iID, 
    sum(case when Tr.Buy=1 then Tr.qty when Tr.Buy=0 then Tr.qty*-1 else 0 end) as TotalQty 
from 
    Trades Tr, ItemMast I
where 
    Tr.iID = I.iID 
    and I.iCode = '1253'
    and Tr.tDate <= '5/13/2015' 
group by 
    I.itemName, I.iID
order by 
    I.itemName, I.iID

I tried to modify the where clause adding Where TotalQty > 0 , but it does not work.

Not sure how to go about with this. I am trying to build this on SQL Server CE.

Appreciate your help.

Thanks

Answer 1

Try use full expression in having clause as below

Select I.itemName, I.iID, sum(case when Tr.Buy=1 then Tr.qty when Tr.Buy=0 then Tr.qty*-1 else 0 end) as TotalQty 
from Trades Tr,ItemMast I
where Tr.iID = I.iID 
and I.iCode = '1253'
and Tr.tDate<= '5/13/2015' 
group by I.itemName, I.iID
having sum(case when Tr.Buy=1 then Tr.qty when Tr.Buy=0 then Tr.qty*-1 else 0 end) > 0
order by I.itemName, I.iID