Procedure returning different values I have a procedure TempSalesUpdateID which gets all ProductName's column in TempSales table and set it's corresponding ProductID.

ALTER PROCEDURE [dbo].[TempSalesUpdateID]
AS
UPDATE T 
SET        T.ProductID = P.ProductID 
FROM       TempSales T 
INNER JOIN Products P 
ON         P.PN=T.ProductName


When I execute it through SQL Server Management Studio it runs perfectly: when it finds a corresponding ID, it fills ProductID column, otherwise leaves it NULL.

When I run it from my C# Windows Form Application, it puts almost random numbers instead of leaving NULL (the ones which doesn't have a corresponding ID).

I say almost because: 13098 rows have value 1 instead of NULL, 14742 rows have value 2 instead of NULL, 13601 value 3, etc.

Could you please help me? I'm really lost here
The problem was solved by using a new connection to execute the procedure.

I think it might help if someone is on the same situation.