How to improve Query Performance

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Hi Everybody,

I have a query which performance i need to improve.
I want to share your experience.

The Query is :

Select * from Customer C where 1=1 AND NOT EXISTS (Select * from Members).

Posted 14-Dec-12 7:55am

Anubhava Dimri

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Jibesh 14-Dec-12 14:03pm

It's really hard to explain with this limited information. without knowing the columns of the table no one could fine tune your query.

SQL Query Optimization is a huge topic and I believe you did some research googling for query optimization is a good way to start

Jörgen Andersson 15-Dec-12 16:13pm

1 = 1 is completely pointless.
Your subquery does not have any condition, so your query will not have any result if there are any rows at all in Members table. And if the members table is empty the result will be the complete Customer table.
There is nothing to tune in this query.

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Jibesh · Answer 1 · 2012-12-14T08:06:00

Solution 1

hope these links helps you to start reading about query optimization
http://www.sqlsteps.com/sql-tutorial-improving-query-performance[^]
http://www.componentace.com/help/absdb_manual/increasesqlperformance.htm[^]

Posted 14-Dec-12 8:06am

Jibesh