FIX: AV or Error 632 on Update w/ Select Count(distinct) Subqu

• Microsoft SQL Server, version 6.0

SYMPTOMS

A thread-level Access Violation (AV) or 632 error may be generated if an UPDATE statement is issued that sets a column in the update table equal to the "SELECT COUNT(DISTINCT column)" results of a subquery. The subquery must contain a comparison expression against a column which contains all null values.

The 632 error will generate the text:

   Error : 632, Severity 20, State 1
   Memmove() was called with a length of n - maximum allowed length is m.

WORKAROUND

Rewrite the query to eliminate the use of the COUNT(distinct) expression within the same statement as the comparison against the null column(s). A possible option would be to select the distinct results into a temporary table and perform futher manipulation on that data set.

STATUS

Microsoft has confirmed this to be a problem in Microsoft SQL Server version 6.0. This problem was corrected in Service Pack 2 for SQL Server version 6.0. For more information, contact your primary support provider.