BUG: UNION with Local Variables GP Faults Server

• Microsoft SQL Server version 4.2 for OS/2
• Microsoft SQL Server, versions 4.2, 4.21, and 4.21a

       NT:  851 (4.2)

SYMPTOMS

If you use a union operator to link two select statements that assign values to local variables, SQL Server for OS/2 will general protection fault (GP fault), and SQL Server for Windows NT will have an access violation. However, in SQL Server for Windows NT, only the client connection that runs the query is terminated. The rest of the clients are not affected.

For example, the following query GP faults SQL Server:

   declare @v int
   select @v=1
   UNION
   select @v=1
   go

CAUSE

SQL Server incorrectly handles the UNION operation if you use the UNION operator to assign multiple values to a local variable.

WORKAROUND

Do not use the UNION operator with local variables. If you are trying to assign different values to a local variable depending on variable conditions, use IF statements instead.

STATUS

Microsoft has confirmed this to be a problem in SQL Server version 4.2 and Microsoft SQL Server versions 4.2, 4.21, and 4.21a. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.