Aggregate functions may return incorrect results in a query that has a correlated subquery. The showplan for the query will show a spool operation followed by a nested loop join.
To resolve this problem, obtain the latest service pack for SQL Server 2000. For additional information, click the following article number to view the article in the
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INF: How to Obtain the Latest SQL Server 2000 Service Pack
You can add a merge or hash join hint in the FROM clause of the inner query to remove the spool operation from the query plan. You can also add appropriate indexes so that the optimizer will choose a different query plan that does not use the spool operation.
Microsoft has confirmed that this is a problem in SQL Server 2000. This problem was first corrected in SQL Server 2000 Service Pack 1.