Question

I have this query that works as desired, but it seems like there should be a better way to accomplish what I want:

SELECT `x`.*
FROM (
    SELECT `m`.`id`,
        `m`.`email`,
        MAX(`s`.`end`) AS `max_end`
    FROM `members` AS `m`
    INNER JOIN `memberships` AS `s`
        ON `m`.`id` = `s`.`member_id`
    GROUP BY `m`.`id`,
        `m`.`email`
) AS `x`
WHERE `x`.`max_end` = '2010-02-28 23:59:59'

I am looking for a member whose membership ends on a certain date. The memberships table has start and end columns contain the dates that the membership is active. I only want to look at the last ending membership period, hence the MAX() and GROUP BY in the sub-query.

Answer 1

This could be rewritten using having:

SELECT `m`.`id`,
    `m`.`email`
FROM `members` AS `m`
INNER JOIN `memberships` AS `s`
    ON `m`.`id` = `s`.`member_id`
GROUP BY `m`.`id`,
    `m`.`email`
HAVING MAX(`s`.`end`) = '2010-02-28 23:59:59'