Is it possible to turn this query into a join? - mysql

Question

This is the query:
SELECT *
FROM square_achievements_achievements
JOIN square_achievements_achievement_counters ON square_achievements_achievement_counters.SAA_ID = square_achievements_achievements.SAA_ID
JOIN square_achievements_counters ON square_achievements_counters.SAC_ID = square_achievements_achievement_counters.SAC_ID
WHERE square_achievements_counters.eventObject = 'CommentEvent'
AND square_achievements_counters.eventType = 'add'
AND square_achievements_achievements.SAA_ID NOT IN
(
SELECT square_achievements_achievements.SAA_ID
FROM square_achievements_achievements
JOIN square_achievements_user_achievements ON square_achievements_user_achievements.SAA_ID = square_achievements_achievements.SAA_ID
WHERE square_achievements_user_achievements.UID = 83
)
If it's possible, would it be more efficient to write this query as a join? If so, how would it be rewritten?

Answer 1

SELECT a.*
FROM achievements a
JOIN achievement_counters ac
ON ac.saac_id = a.saa_id
JOIN counters c
ON c.sac_id = ac.sac_id
WHERE c.eventObject = 'CommentEvent'
AND c.eventType = 'add'
AND a.saa_id NOT IN
(
SELECT saa_id
FROM user_achievements
WHERE uid = 83
)
This is pretty good.
If you want joins, use this:
SELECT a.*
FROM achievements a
JOIN achievement_counters ac
ON ac.saac_id = a.saa_id
JOIN counters c
ON c.sac_id = ac.sac_id
LEFT JOIN
user_achievements ua
ON ua.uid = 83
AND ua.saa_id = a.saa_id
WHERE c.eventObject = 'CommentEvent'
AND c.eventType = 'add'
AND ua.saa_id IS NULL

Answer 2

I prefer to use correlation names to improve the readability of the code
Try this:
SELECT *
FROM square_achievements_achievements a
JOIN square_achievements_achievement_counters b ON b.SAAC_ID = a.SAA_ID
JOIN square_achievements_counters c ON c.SAC_ID = b.SAC_ID
JOIN square_achievements_user_achievements d on d.SAA_ID = a.SAA_ID
JOIN square_achievements_user_achievements u on d.SAA_ID = u.SAA_ID AND u.UID = 83
WHERE c.eventObject = 'CommentEvent'
AND a.eventType = 'add'