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sqlfresher2k7
Aged Yak Warrior
623 Posts |
 Posted - 2012-04-20 : 14:06:41
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| how do i rewrite the below to improve the performance..delete from Test.dbo.Student WHERE VAL LIKE '%JOIN%' and VAL NOT LIKE '%;%;%' delete from Test.dbo.Student WHERE VAL LIKE '%Completed%' and VAL NOT LIKE '%;%;%;%' |
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visakh16
Very Important crosS Applying yaK Herder
52326 Posts |
Posted - 2012-04-20 : 15:06:32
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| Queries seraching for patterns like this wont perform well. Can I ask what exactly you're trying to detect using above conditions?------------------------------------------------------------------------------------------------------SQL Server MVPhttp://visakhm.blogspot.com/ |
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sqlfresher2k7
Aged Yak Warrior
623 Posts |
Posted - 2012-04-20 : 16:15:04
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| There is no index defined on the table howerver the val is varchar type.Would it improve the performance if the index is created.. |
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robvolk
Most Valuable Yak
15732 Posts |
Posted - 2012-04-20 : 16:38:21
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| Unlikely. Leading wildcard patterns cannot use an index for a seek, at best it would have to scan the index. |
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sqlfresher2k7
Aged Yak Warrior
623 Posts |
Posted - 2012-04-20 : 17:12:25
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| Thanks What is possible solution to my query for performance.. |
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robvolk
Most Valuable Yak
15732 Posts |
Posted - 2012-04-20 : 17:46:51
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| It's hard to say. Full-text indexing can help find words, but will ignore punctuation. What are you storing in that column? |
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visakh16
Very Important crosS Applying yaK Herder
52326 Posts |
Posted - 2012-04-21 : 13:15:55
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quote:
Originally posted by sqlfresher2k7
Thanks What is possible solution to my query for performance..
You didnt answer my questionwhat is the purpose of used query?------------------------------------------------------------------------------------------------------SQL Server MVPhttp://visakhm.blogspot.com/ |
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