改進sql查詢選擇玩遊戲的數量和玩家贏得的遊戲數量

Question

我有一些問題，我無法解決的sql查詢。

我有2個表：

players: id, name 
games: id, name, player1_id, player2_id, winner_id 

現在我想要得到的遊戲總量，贏得了每一個玩家。

目前我與子選擇這樣做：

SELECT player.name AS name, 
(SELECT COUNT(id) FROM replays AS replay WHERE replay.player1_id = player.id OR replay.player2_id = player.id) AS games, 
(SELECT COUNT(id) FROM replays AS replay WHERE replay.winner_id = player.id) AS wins 
FROM players AS player 

但首先它是非常緩慢的。 而且，我無法進行復雜的搜索查詢，例如搜索贏得超過次數的遊戲或者遊戲次數少的遊戲。

你有什麼想法，我該如何改進這個查詢？

預先感謝您。

Answer 1

嘗試這樣：

select a.player_id, p.name, count(*) as GamesCount, 
    count(case when g.winner_id = a.player_id then 1 end) as WinsCount 
from (
    select player1_id as player_id 
    from games 
    union 
    select player2_id as player_id 
    from games 
) a 
inner join games g on a.player_id = g.player1_id 
    or a.player_id = g.player2_id 
inner join players p on a.player_id = p.id 
group by a.player_id, p.name