Re: Group by

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The only SELECT is on MAX('timestamp'). There is really nothing to Group BY in this query.

Dewey

Philip Thompson wrote:
Hi.

In a mysql query, it is recommended that "GROUP BY" fields be indexed? Using EXPLAIN on one of my queries, I noticed no change between having indexed by GROUP BY field and not indexing it. Any thoughts would be appreciated.

In this example, should `history_field` be indexed...?

SELECT MAX(`timestamp`) AS `max_ts` FROM `history` WHERE `req_id` = 17 AND `history_record_id` = 35
GROUP BY `history_field`

Thanks,
~Philip


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