MySQL：內部加入在這個聲明中是最有效率的嗎？

Question

下面的MySQL語句需要很長時間才能執行，我想因爲我使用的是gameId IN。

我認爲最有效的方法是使用一個INNER JOIN，但我是新來的MySQL，我不能拿出INNER JOIN聲明。你能幫我解決嗎？如果有比INNER JOIN更有效的方法，我想用這個，我只是不確定是否有。

聲明，需要更高效：

SELECT championId 
FROM match_up WHERE 
gameId IN 
(
    SELECT gameId 
    FROM match_up 
    GROUP BY gameId 
    HAVING SUM(championId IN (19, 23, 40) AND win = 1) = 3 
    AND SUM(championId IN (7, 18) AND win = 0) = 2 
) 

預先感謝您的幫助和知識！

Answer 1

如何像

SELECT m.championId 
FROM match_up m INNER JOIN 
(
    SELECT gameId 
    FROM match_up 
    GROUP BY gameId 
    HAVING SUM(championId IN (19, 23, 40) AND win = 1) = 3 
    AND SUM(championId IN (7, 18) AND win = 0) = 2 
) s ON m.gameID = s.gameID 

看一看Row Subqueries和Subqueries in the FROM Clause

Answer 2

這裏的區別是，可能會在match_up(gameId, win, championId)與索引執行遺囑的方法：

select * 
from match_up m 
where 3 = (select count(*) 
      from match_up m2 
      where m2.gameId = m.gameId and 
       m2.championId IN (19, 23, 40) and 
       m2.win = 1 
     ) and 
     2 = (select count(*) 
      from match_up m2 
      where m2.gameId = m.gameId and 
       m2.championId IN (7, 18) and 
       m2.win = 0 
     );