Question

我有2张桌子

create table players
(name text,
 id serial primary key);

create table matches
 (winner integer references players(id),
  loser integer references players(id),
  id serial primary key);

我必须制作一个名为“standings”的表，其中包含：

player_id,player_name,total_wins,total_matches

如何进行？

Answer 1

这样的事情：

select p.id, p.name, 
       count(w.id) as total_wins, 
       count(l.id) + count(w.id) as total_matches
from players p 
  left join matches w on w.winner = p.id
  left join matches l on l.loser = p.id
group by p.id, p.name;

在线示例：http://rextester.com/EHDCG19917

在锦标赛中查找排名表

1 个答案: