mysql 聚合函数

1.sum 用法

有这种类型的数据:

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

你想要条件聚合:

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;




如果执行：where good_id=16 and hascount>1 就会报错，