ORDER BY Not working with GROUP BY - php

Question

I have written sql code using group by and order by but in here order by not working can any one help me
SELECT " . DB_PREFIX . "leaderboard_scores.* , SUM(" . DB_PREFIX . "leaderboard_scores.score) as total_score, " . DB_PREFIX . "customer.firstname,
" . DB_PREFIX . "customer.lastname
FROM " . DB_PREFIX . "leaderboard_scores
JOIN " . DB_PREFIX . "customer ON " . DB_PREFIX . "leaderboard_scores.philips_store_id = " . DB_PREFIX . "customer.customer_id
GROUP BY " . DB_PREFIX . "leaderboard_scores.phi_store_id
ORDER BY " . DB_PREFIX . "leaderboard_scores.week DESC
This query work without php errors but given middle rows without giving top weeks. weeks store using times stamp
actual query
SELECT rc_leaderboard_scores.* , SUM(rc_leaderboard_scores.score)
as total_score, rc_customer.firstname, rc_customer.lastname
FROM rc_leaderboard_scores
JOIN rc_customer
ON rc_leaderboard_scores.phi_store_id = rc_customer.customer_id
GROUP BY rc_leaderboard_scores.phi_store_id
ORDER BY rc_leaderboard_scores.week DESC

Answer 1

If you need to return the last record for every customer, you need a JOIN with a subquery that returns MAX(week) for every customer id:
SELECT
rc_leaderboard_scores.*,
m.total_score,
rc_customer.firstname,
rc_customer.lastname
FROM
(SELECT phi_store_id,
MAX(`week`) as max_week,
SUM(score) as total_score,
FROM rc_leaderboard_scores
GROUP BY phi_store_id) m
INNER JOIN
rc_leaderboard_scores
ON rc_leaderboard_scores.phi_store_id = m.phi_store_id
AND rc_leaderboard_scores.`week` = m.max_week
INNER JOIN
rc_customer ON m.phi_store_id = rc_customer.customer_id