如何简化此游戏统计查询？

Question

如何简化此游戏统计查询？

这段代码按预期工作，但我很长很令人毛骨悚然。

select p.name, p.played, w.won, l.lost from

(select users.name, count(games.name) as played

from users

inner join games on games.player_1_id = users.id

where games.winner_id > 0

group by users.name

union

select users.name, count(games.name) as played

from users

inner join games on games.player_2_id = users.id

where games.winner_id > 0

group by users.name) as p

inner join

(select users.name, count(games.name) as won

from users

inner join games on games.player_1_id = users.id

where games.winner_id = users.id

group by users.name

union

select users.name, count(games.name) as won

from users

inner join games on games.player_2_id = users.id

where games.winner_id = users.id

group by users.name) as w on p.name = w.name

inner join

(select users.name, count(games.name) as lost

from users

inner join games on games.player_1_id = users.id

where games.winner_id != users.id

group by users.name

union

select users.name, count(games.name) as lost

from users

inner join games on games.player_2_id = users.id

where games.winner_id != users.id

group by users.name) as l on l.name = p.name

如您所见，它由3个重复部分组成，用于检索：

玩家姓名和他们玩的游戏数量

球员名称和他们赢得的比赛数量

球员姓名和他们输掉的比赛数量

每个人还包括两部分：

玩家姓名以及他们作为player_1参与的游戏数量

玩家姓名以及他们作为player_2参与的游戏数量

怎么可以简化？

结果如下：

           name            | played | won | lost 

---------------------------+--------+-----+------

 player_a                  |      5 |   2 |    3

 player_b                  |      3 |   2 |    1

 player_c                  |      2 |   1 |    1

Answer 1

这是相关子查询可以简化逻辑的情况：select u.*, (played - won) as lostfrom (select u.*,              (select count(*)               from games g              where g.player_1_id = u.id or g.player_2_id = u.id             ) as played,              (select count(*)               from games g              where g.winner_id = u.id             ) as won      from users u     ) u;这假设没有联系。