Hi Krystian,
Try this query, it will show only values > 0 for the agregate of minStock:
Select
t0.ItemCode [Kod Produktu],
t1.ItemName [Nazwa towaru],
sum (t0.OnHand) [W magazynie],
sum (t0.onorder) [Zamowione],
sum (t0.iscommited) [potwierdzone],
sum(isnull(t0.MinStock,0)) [Min],
sum (isnull(t0.MaxStock,0)) [Max],
sum ((t0.OnHand-isnull(t0.minStock,0))*(-1))[niedobor do min] ,
case
when sum(isnull(t0.MaxStock,0))=0 then 0
else sum (( t0.OnHand-isnull(t0.MaxStock,0))*(-1))
end [niedobor do max]
from OITW t0
join oitm t1 on t1.ItemCode=t0.ItemCode
where t0.WhsCode IN ('wyr', 'mz1','mz2','mz3','mz4')
GROUP BY t0.itemcode, t1.ItemName
HAVING sum(isnull(t0.MinStock,0)) > 0
hope this helps,
juanpa