• It would be useful to know the exact error condition being generated. However I would work towards simplifying the expression by

    a) including an additional OLE SRCE dataset which included the basic transformations, ie

    SELECT 1 AS CASE_STATUS

    ,'A1021002' AS RESULT

    UNION ALL

    SELECT 2 AS CASE_STATUS

    ,'A1021002' AS RESULT

    etc etc

    UNION ALL

    SELECT 10 AS CASE_STATUS

    ,null AS RESULT

    etc etc

    b) doing a merge join wth the primary data source to return the results for everything other than case_status 10

    c) having the derived column expression to include the additonal logic for Case_Status 10 and the associated Reject_Reason (s)