Ms sql server sql优化技巧

SET   STATISTICS   PROFILE   ON
SET   STATISTICS   IO   ON
SET   STATISTICS   TIME   ON
SELECT * FROM userinfo WHERE Name IS NOT  NULL AND  Name = '刘'
SELECT * FROM userinfo WHERE   Name = '刘'
SET   STATISTICS   PROFILE   OFF
SET   STATISTICS   IO   OFF
SET   STATISTICS   TIME   OFF