Typically, in a relational database management system (RDBMS), nulls represent the absence of data. That is, RDBMS nulls do not sort or compare because there is no data on which to operate. However, in SAS, there is the concept of a missing value, which is quite different.

In SAS, using the IN operator where single quotation marks (‘ ’) are used to represent a null might return unexpected results.

In the following query, SAS passes the WHERE clause as written. This prevents most databases from finding the rows where the variable A was NULL. This happens when the database does not consider a NULL as equal to any value, so rows with NULLS would not be determined to be a match:

To work around this issue, rewrite the query to something similar to the following:

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

Operating System and Release Information

A fix for this issue for Base SAS 9.4_M1 is available at:

A fix for this issue for Base SAS 9.4_M2 is available at: