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Difference between Corrrelated Subquery and Joins

 
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Sudeshna Sarkar

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Joined: 11 Sep 2008
Posts: 29
Location: Kolkata

PostPosted: Sat May 15, 2010 3:18 pm    Post subject: Difference between Corrrelated Subquery and Joins
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I have been asked a generic question as to what is the Difference between Corrrelated Subquery and Joins? The more important thing which one is really more efficient!

I have read topics from many forums and questions/answers but not really a concrete difference in terms of performance, at max I read that it all depends on the Optimizer, the complexity of the query and indexes that are used.

Do we really have a performance difference in general?
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dbzTHEdinosauer

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PostPosted: Sat May 15, 2010 5:50 pm    Post subject:
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Rudy Limeback wrote:
The best answer is: it depends. It depends on which database system you're using. It depends on how sophisticated the optimizer is. It depends on which indexes you have defined on the columns. It depends on how complex the query is.
...
The final answer? You will have to run performance tests on your own tables with your own subqueries and joins, and compare the results.
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Sudeshna Sarkar

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PostPosted: Sun May 16, 2010 7:08 pm    Post subject: Reply to: Difference between Corrrelated Subquery and Joins
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thanks much!
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