如何结合multiple COUNT（）和GROUP BY实现MySQL查询

所以我有这类数据：

id      date            user_id    result
1       2015-05-04      1          win
2       2015-05-06      1          loss
3       2015-05-09      2          loss
4       2015-05-10      2          win
5       2015-05-16      1          win

我需要按大多数赢家对前4名用户进行排序。但我还需要得到这4位头号赢家的损失数字。因此，当我查询这个特定集合时，我会得到：

user    wins    losses
1       2       1
2       1       1

我知道如何通过使用以下工具与用户id一起获得胜利：

SELECT user_id, COUNT(id) AS wins FROM table WHERE result = 'win' GROUP BY user_id ORDER BY COUNT(id) DESC LIMIT 4

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但是，如果使用相同的查询，我将如何获得前4名球员的损失？我知道这是可能的，但只是不知道如何执行它！有什么想法吗？

您想要条件聚合：

SELECT user_id, sum(result = 'win') AS wins, sum(result = 'loss') as losses
FROM table
GROUP BY user_id
ORDER BY wins DESC
LIMIT 4;

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您需要条件聚合：

SELECT user_id, sum(result = 'win') AS wins, sum(result = 'loss') as losses
FROM table
GROUP BY user_id
ORDER BY wins DESC
LIMIT 4;

---

您需要条件聚合：

SELECT user_id, sum(result = 'win') AS wins, sum(result = 'loss') as losses
FROM table
GROUP BY user_id
ORDER BY wins DESC
LIMIT 4;

---

您需要条件聚合：

SELECT user_id, sum(result = 'win') AS wins, sum(result = 'loss') as losses
FROM table
GROUP BY user_id
ORDER BY wins DESC
LIMIT 4;

---

我会这样做：

SELECT user_id, 
  SUM(CASE WHEN result='win' THEN 1 ELSE 0 END) AS wins,
  SUM(CASE WHEN result='loss' THEN 1 ELSE 0 END) AS losses 
FROM table1 
GROUP BY user_id 
ORDER BY wins DESC
LIMIT 4

---

小提琴在这里：

我会这样做：

SELECT user_id, 
  SUM(CASE WHEN result='win' THEN 1 ELSE 0 END) AS wins,
  SUM(CASE WHEN result='loss' THEN 1 ELSE 0 END) AS losses 
FROM table1 
GROUP BY user_id 
ORDER BY wins DESC
LIMIT 4

---

小提琴在这里：

我会这样做：

SELECT user_id, 
  SUM(CASE WHEN result='win' THEN 1 ELSE 0 END) AS wins,
  SUM(CASE WHEN result='loss' THEN 1 ELSE 0 END) AS losses 
FROM table1 
GROUP BY user_id 
ORDER BY wins DESC
LIMIT 4

---

小提琴在这里：

我会这样做：

SELECT user_id, 
  SUM(CASE WHEN result='win' THEN 1 ELSE 0 END) AS wins,
  SUM(CASE WHEN result='loss' THEN 1 ELSE 0 END) AS losses 
FROM table1 
GROUP BY user_id 
ORDER BY wins DESC
LIMIT 4

---

小提琴在这里：

啊，我看戈登已经回答了。请注意，并非所有数据库都支持他使用的条件聚合。但是再说一遍，限制也不是。啊，我看戈登已经回答了。请注意，并非所有数据库都支持他使用的条件聚合。但是再说一遍，限制也不是。啊，我看戈登已经回答了。请注意，并非所有数据库都支持他使用的条件聚合。但是再说一遍，限制也不是。啊，我看戈登已经回答了。请注意，并非所有数据库都支持他使用的条件聚合。但是，同样的，

LIMIT

。