Validation Error

Hi,

I am looking for a bit of assistance with a SQL condition I am writing within Validation. Basically, we are trying to create a 'Shopping list' for buyers. The whole point is so when a buyer is creating a Purchase order for a particular BPcode if someone has something outstanding it will flash up with a message to buy whatever is on the list.

I have started off with a UDT called @purchasing and anyone can go into this and edit this with UDF Handler but I am trying to get the validation to look up within this table to then alert the user of any outstanding to buy. If there isn't anything to buy it wont show anything.

I have got this so far but I keep getting error 'Error during use of B1 Validation System ID=14: Error during Execution of B1 Validation'

IF(SELECT T0.U_CardCode
FROM @PURCHASING T0
WHERE T0.U_CardCode = $[$4.0.0])
) <> ''
BEGIN
SELECT 'True' FOR BROWSE
END

Thanks,

George.