BUG: SUM in Subquery Has NULL Precision and Scale

• Microsoft SQL Server, version 6.5

SYMPTOMS

A SELECT that contains a subquery that performs a SUM will have scale and precision set to NULL for the summed field. For example, the following statement will show this behavior:

   SELECT f1, (SELECT SUM(f2) SUMCOL FROM table2) FROM table1

The net effect of this is that applications like Microsoft Access will use the summed field as Text(255) because of the NULL scale and precision. As a result, Access will not allow numeric processing on the field.

WORKAROUND

To work around this problem, create a view that contains the subquery with the SUM, and use a join to bring the two queries together. The following script shows an example of the workaround:

   create table abc1
   (
   mykey integer
   )
   go

   create table abc2
   (
   mykey integer,
   mybucks money
   )
   go

   create view abcview2
   as
   select mykey, mysum(mybucks) mycol from abc group by mykey
   go

   create view abcview
   as
   select abc1.mykey, abcview2.mycol from abc1 join abcview2 on
   abc1.mykey = abcview2.mykey
   go

STATUS

Microsoft has confirmed this to be a problem in Microsoft SQL Server version 6.5. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.