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JOIN issue [message #453]

Wed, 06 December 2006 03:18

migandhi
Messages: 8
Registered: December 2006

Junior Member

is the join that may be LEFT OUTER or RIGHT OUTER or INNER or just JOIN the same as in MSSQL .
i am particularly interested in LEFT OUTER JOIN .

And i dont dare to use GROUP BY or DISTINCT as the query takes too long in execution.

My issue is proper migration from MSSQL to MySQL , which is becoming difficult at each step.

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Re: JOIN issue [message #454 is a reply to message #453 ]

Wed, 06 December 2006 06:59

Peter
Messages: 405
Registered: August 2006

Senior Member
Super Guru

JOIN semantic is the same, however query execution can be quite different - MySQL only supports nested loops join method which can be inefficient for complex queries.

Also note MySQL does not support FULL OUTER JOIN (LEFT/RIGHT are OK)

Peter Zaitsev, MySQL Performance Expert
MySQL Performance Blog - http://www.mysqlperformanceblog.com
MySQL Consulting http://www.mysqlperformanceblog.com/mysql-consulting/

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