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Re: multi-part index and when it is used?
Posted by: Peter Halliday
Date: January 13, 2005 07:18AM

The only query you listed that might not use the index is SELECT * FROM phonebook; The reason that one might not is because it retrieves too much data. The only way it would use an index would be if the index was a covering index (ie. * was all part of the same index.

What do you mean by that statement? Especially the comment about the covering index.

Also if you did SELECT * FROM phonebook ORDER BY lastName, firstName, middleInitial that would use the index I've created on that? Or would it do whichever it deems as the most optimal?

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Re: multi-part index and when it is used?
January 13, 2005 07:18AM

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