sql性能分析

/*
DBCC DROPCLEANBUFFERS
DBCC FREEPROCCACHE
*/
SET STATISTICS IO ON
SET STATISTICS TIME ON

SELECT TOP 10 *
FROM UserTraces AS ut1
WHERE ActionID<>2
  AND NOT EXISTS(
   SELECT 1
   FROM UserTraces
   WHERE ExtensionID1=ut1.ExtensionID1 AND ActionID<>2 AND CreateDate>ut1.CreateDate
   )
ORDER BY CreateDate DESC

SELECT TOP 10 *
  FROM UserTraces AS t1
   Where EXISTS
   (
      SELECT *
      FROM UserTraces AS t2
      WHERE ActionID<>2
      GROUP BY ExtensionID1
      HAVING ExtensionID1 = t1.ExtensionID1
    and max(CreateDate) = t1.CreateDate
   )
   ORDER BY CreateDate DESC

SET STATISTICS TIME OFF
SET STATISTICS IO OFF

posted on 2008-05-30 14:24 Randy0528 阅读(393) 评论(0) 编辑收藏举报