计算游戏积分的sql

我有一张桌子，上面有足球比赛。

桌上游戏：

id
team_home (varchar)
team_away (varchar)
team_home_goals INT
team_away_goals INT

要插入我这样做：

insert into games values(null, 'Liverpool', 'Chelsea', 0, 0);
insert into games values(null, 'Arsenal', 'City', 1, 2);
insert into games values(null, 'ManUTD', 'Tottenham', 2, 1);

insert into games values(null, 'Chelsea', 'Arsenal', 0, 0);
insert into games values(null, 'Tottenham', 'Liverpool', 1, 0);
insert into games values(null, 'City', 'ManUTD', 2, 1);

我需要创建一个查询来获取包含位置的表。 根据上面的插入，表格将是：

1 - City 6 points  
2 - ManUTD 3 points
3 - Tottenham 3 points
4 - Chelsea 2 points
5 - Liverpool 1 point
6 - Arsenal 1 point

我为此创建的查询是针对“主队”或“客队”。 我可以运行这个查询两次，然后将其他地方的点相加。但我想知道是否有一种聪明的方法 只需一个查询即可完成所有操作。这就是我现在所拥有的（我运行了两次，第一次是主队，然后是客队）：

select 
team_home,
sum
(
case 
when team_home_goals > team_away_goals then 3
when team_home_goals = team_away_goals then 1
when team_home_goals < team_away_goals then 0
end
)
as points
from 
games
group by team_home;

你可以使用UNION:

SELECT team, SUM(points) AS total_points
FROM (
  SELECT team_home AS team, 
         CASE 
            WHEN team_home_goals > team_away_goals THEN 3
            WHEN team_home_goals = team_away_goals THEN 1
            ELSE 0
         END AS points
  FROM games

  UNION ALL

  SELECT team_away AS team, 
         CASE 
            WHEN team_away_goals > team_home_goals THEN 3
            WHEN team_away_goals = team_home_goals THEN 1
            ELSE 0
         END AS points
  FROM games ) AS t
GROUP BY team
ORDER BY total_points DESC

演示在这里 http://sqlfiddle.com/#!9/726a5/3