Question

I am still getting my head around MySQL INDEXES… A quick question…

I have a table that stores a members location. It has a member_id and location_id columns… I do a MySQL query to find all the locations for a specific member…

Would it be better to setup an INDEX like this:

ALTER TABLE `members_locations` ADD INDEX `member_location` ( `member_id` , `location_id` )

Or should I separate them like this>

ALTER TABLE `members_locations` ADD INDEX `member_id` ( `member_id` );
ALTER TABLE `members_locations` ADD INDEX `location_id` ( `location_id` );

Does it make any difference?

Answer 1

This article should be helpful.

Here’s an example from it:
ALTER TABLE buyers ADD INDEX idx_name_age(first_name,last_name,age);

Here’s another article showing the difference between using a multi-column index and several single-column indexes.