MySql:是否可以“SUM IF"或“COUNT IF"?
2021-11-20 00:00:00
mysql
我有一列小时"我有一列种类"(可以是 1,2 或 3)
I have a column 'hour' I have a column 'kind' (it can be 1,2 or 3)
我想做类似的事情:
SELECT count(id), SUM(hour) as totHour, SUM( IF ( kind = 1, 1, 0 ) ) as countKindOne
或
SELECT count(id), SUM(hour) as totHour, COUNT( IF ( kind = 1 ) ) as countKindOne
但是 mysql 告诉我我有一个错误...错误是什么!?
But mysql tell me I've an error... what's the error!?
请参阅此 stackoverflow 主题:MySQL SUM IF 字段 b = 字段 a
Please see this stackoverflow topic: MySQL SUM IF field b = field a
...我无法回复这个...
.. I'm not able to reply this ...
推荐答案
您可以使用 CASE
语句:
SELECT count(id),
SUM(hour) as totHour,
SUM(case when kind = 1 then 1 else 0 end) as countKindOne
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