改进sql查询选择玩游戏的数量和玩家赢得的游戏数量

Question

我有一些问题，我无法解决的sql查询。

我有2个表：

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

现在我想要得到的游戏总量，赢得了每一个玩家。

目前我与子选择这样做：

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 

但首先它是非常缓慢的。 而且，我无法进行复杂的搜索查询，例如搜索赢得超过次数的游戏或者游戏次数少的游戏。

你有什么想法，我该如何改进这个查询？

预先感谢您。

Answer 1

尝试这样：

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