Creating a character column (using the CASE expression) to evaluate a numeric column can cause performance problems when you are working with database management system (DBMS) tables. The problem occurs because of a failure in the implicit Pass-Through facility. This failure causes all rows of the DBMS table or tables to be returned to the SAS^® System before the CASE expression is evaluated.

You can use the SASTRACE= system option in an OPTIONS statement to determine whether suspected performance problems are a result of the CASE expression.

   options sastrace=',,d,d' sastraceloc=saslog nostsuffix;

If performance problems are a result of the CASE expression, you will see the following messages in the SAS log:

  SAS_SQL:  Types mismatch. Character data expected.
  SAS_SQL:  Unable to convert the query to a DBMS specific SQL statement due to an error.
  ACCESS ENGINE:  SQL statement was not passed to the DBMS, SAS will do the processing.

Select the Hot Fix tab in this note to access the hot fix for this issue.

Operating System and Release Information

A fix for SAS 9.1.3 (9.1 TS1M3) for this issue is available at:

A fix for SAS 9.1.3 (9.1 TS1M3) with Asian Language Support (DBCS) for this issue is available at: