sql - Select most recent row with GROUP BY in MySQL

Question

I'm trying to select each user with their most recent payment. The query I have now selects the users first payment. I.e. if a user has made two payments and the payment.ids are 10 and 11, the query selects the user with the info for payment id 10, not 11.

  SELECT users.*, payments.method, payments.id AS payment_id 
    FROM `users` 
         LEFT JOIN `payments` ON users.id = payments.user_id 
GROUP BY users.id

I've added ORDER BY payments.id, but the query seems to ignore it and still selects the first payment.

All help appreciated. Thanks.

Answer 1

You want the groupwise maximum; in essence, group the payments table to identify the maximal records, then join the result back with itself to fetch the other columns:

SELECT users.*, payments.method, payments.id AS payment_id
FROM   payments NATURAL JOIN (
  SELECT   user_id, MAX(id) AS id 
  FROM     payments
  GROUP BY user_id
) t RIGHT JOIN users ON users.id = t.user_id

Note that MAX(id) may not be the "most recent payment", depending on your application and schema: it's usually better to determine "most recent" based off TIMESTAMP than based off synthetic identifiers such as an AUTO_INCREMENT primary key column.