Question

我正在写一个简单的足球数据库，在那个数据库中，我希望球队在欧足联进行比赛，但要计算欧足联的胜利数。

球队可以打欧足联，结果应该是'赢''平局'或'输'

为此，我写了这个查询，但我不知道如何更改count语句，因为此查询给出了在UEFA中玩的每个团队的匹配数。

SELECT t.name, count(*) as Wins
FROM Teams t, Matches m
WHERE competion = 'UEFA' AND t.name = m.team
GROUP BY t.name

Answer 1

使用适当的标准，它看起来像：

SELECT t.name, count(*) as matches,
sum(case when result = "win" then 1 else 0 end) as wins,
sum(case when result = "draw" then 1 else 0 end) as draws,
sum(case when result = "loss" then 1 else 0 end) as losses
FROM Teams t, Matches m
WHERE competion = 'UEFA' AND t.name = m.team
GROUP BY t.name

MySQL，过滤但计算不同的值

1 个答案: