Опитайте да направите това:
Select Acct,Period,F_year, Sum(isnull(cast(AMT as float),0)) as Amt
from dbo.Cos
Group By Acct,Period,F_year
Опитайте да направите това:
Select Acct,Period,F_year, Sum(isnull(cast(AMT as float),0)) as Amt
from dbo.Cos
Group By Acct,Period,F_year