Question

I’ve got reporting of a user’s score every time it happens. Now I want to show the best score a user has had. The table set up is like this:

Player(id, name)

PlayerHasAchievement(id, playerId,
achievementId)

Achievement(id, type, amount, time)

This is what I have right now:

SELECT MAX(ach.amount) as amount, p.username, ach.time
FROM  achievement as ach
INNER JOIN playerHasAchievement as playAch ON ach.id = playAch.id
INNER JOIN player as p ON p.userId = playAch.userid
WHERE ach.type = 2
GROUP BY amount
ORDER by `amount` DESC
LIMIT $amount

I tried to select it distinctly but it didn’t work.

Answer 1

The problem is the the ach.time you are getting is not the same row as the MAX(amount). Join another subquery to get the MAX(amount) first.

Note: In the table definitions you posted, playerHasAchievement has a field playerId not userId

SELECT MAX(ach.amount) as amount, p.username, MAX(ach.time) MaxTime
FROM  achievement as ach
  INNER JOIN playerHasAchievement as playAch ON ach.id = playAch.id
  INNER JOIN player as p ON p.userId = playAch.playerId
  INNER JOIN (
    SELECT playAch.playerId, MAX(ach.amount) as MaxAmount
    FROM  achievement as ach
      INNER JOIN playerHasAchievement as playAch ON ach.id = playAch.id
    WHERE ach.type = 2
    GROUP BY playAch.playerId
  ) g ON p.playerId = g.playerId AND ach.amount = g.MaxAmount
WHERE ach.type = 2
GROUP BY p.playerId
ORDER by `amount` DESC
LIMIT $amount";

The reason why we group the outer query, is to avoid ties – say a player had the same score twice.