Avoiding subqueries in SQL for big gains

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Avoiding subqueries in SQL for big gains

published 2 months, 18 days ago, submitted by UnicornNinja 2 months, 18 days ago

thebrainparasite.com — Some people are just unaware of the alternatives to performing a sub query. The performance gains can be substantial if you put the database engine to use!

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Comments:

You know, articles like this are painfully useless without any kind of look at what the DB does to optimize queries. His example query is so braindead as to be useless, though I'm mildly surprised that MySQL doesn't optimize it to something smarter.

In many cases, SQL Server will use the exact same execution plan for equivalent subquery and join based selects.

posted by

mrkurt 2 months, 18 days ago

Speaking of brain dead, at least I can form complete sentences. Also, SQL Server will not perform the same execution plan for sub queries beyond the simplest scenario. wonk wonk

posted by UnicornNinja 2 months, 18 days ago