Microsoft KB Archive/167779

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FIX: Query Slow w/ ORDER BY DESC on Table w/ Composite Index

Article ID: 167779

Article Last Modified on 10/16/2003



APPLIES TO

  • Microsoft SQL Server 6.5 Standard Edition



This article was previously published under Q167779

BUG #: 16669 (6.5)

SYMPTOMS

An ORDER BY DESC query against a table that has a non-clustered composite index may take significantly longer to run than the equivalent ASC query. This difference is especially noticed in cases in which a WHERE clause contains an equivalency test of an indexed column (including the most significant) and a constant value.

WORKAROUND

To work around this problem, select the result set (ASC) into a temporary table, then run the ORDER BY DESC query only on the results of a select from the temporary table.

Another option, for certain numeric columns, is to multiply the key by -1 and then run the ORDER BY ASC query.

STATUS

Microsoft has confirmed this to be a problem in Microsoft SQL Server version 6.5. This problem has been corrected in U.S. Service Pack 3 for Microsoft SQL Server version 6.5. For more information, contact your primary support provider.


Additional query words: descending

Keywords: kbbug kbfix kbprogramming kbusage KB167779