Effects of order of columns, while defining an index on them, on the performance of the queries

Posted by Hossein on Stack Overflow See other posts from Stack Overflow or by Hossein
Published on 2010-05-13T22:21:30Z Indexed on 2010/05/13 22:24 UTC
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Hi, Does order of the columns in an Index definition for a table in a database has any effect on the performance? for e.g. are these two queries different ? CREATE INDEX xxx ON tablex(col1,col2) CREATE INDEX xxx ON tablex(col2,col1)

what about the in case that I use a BTREE index? I am using Mysql. thanks

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