Testing for Null in Stored Proc Return Value

I have a Function which might return a Null Value. As you can see I am using vbNull which is failing "Invalid use of Null".
How should I test for this?
Private Function CreInvData(ByVal sStoredProcName As String) As Long
Dim oCmd As New ADODB.Command
Dim oParam As ADODB.Parameter
Set oCmd.ActiveConnection = invConn
oCmd.CommandText = sStoredProcName
oCmd.CommandType = adCmdStoredProc
oCmd.Parameters.Append oCmd.CreateParameter("clCode", adVarChar, adParamInput, 4, sClCode)
oCmd.Parameters.Append oCmd.CreateParameter("chgRate", adInteger, adParamInput, , i)
oCmd.Parameters.Append oCmd.CreateParameter("clStRate", adCurrency, adParamInput, , clStRate)
oCmd.Parameters.Append oCmd.CreateParameter("W", adVarChar, adParamInput, 1, W)
oCmd.Parameters.Append oCmd.CreateParameter("Total", adCurrency, adParamReturnValue)
If oCmd.Parameters("Total") = vbNull Then
    total = 0
    total = oCmd.Parameters("Total")
End If 

Open in new window

Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Why not handle this inside your stored procedure?

Something like:

SELECT ISNULL(Total, 0) AS Total

Open in new window

Total gets 0 if it is null.

The way you are using it, you are treating NULL as a value and it is not.
eharfordAuthor Commented:
My Stored Proc is as follows how would I phrase it?
ALTER PROCEDURE [dbo].[zInvCount]
		@clCode nvarchar(4),
		@chgRate int,
		@clStRate float,
		@W nvarchar(1),
		@Val float OUTPUT
 SELECT @Val = SUM((Depth * Height * Width)/100000) * @clStRate from PartInvent WHERE clCode = @clCode and chgRate = @chgRate and WIssued = 0 and Left(Plocation,1) = @W 

Open in new window

I don't see where you are using Total in your stored proc.

So, try this in your original post

If oCmd.Parameters("Total") = System.DbNull.Value Then
    total = 0
    total = oCmd.Parameters("Total")

Open in new window

Sql server understands that better

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
eharfordAuthor Commented:
I am naming "Total" when creating the Return Value parameter:
oCmd.Parameters.Append oCmd.CreateParameter("Total", adCurrency, adParamReturnValue)
The value coming back is Null (or a Currency Value).
As to your suggestion I am using vb6 and I don't think System.dbNull.Value is vb6 syntax. I would have thought vbNull would work but it doesn't for some reason. Is it perhaps the adCurrency datatype I am using?
Thanks for your help.
eharfordAuthor Commented:
I have worked it out in Stored Proc. Thanks for your suggestion.
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.