将多个 MySQL 查询合并为一个

Question

我正在尝试编写一个查询，我可以在其中每 3 个月计算一次数据库事务表中不同的 user_id 的计数。

如果我执行以下操作，我可以手动获得结果

SELECT COUNT(DISTINCT(user_id)) FROM transactions WHERE DATE(created_at) BETWEEN "2011-01-01" AND "2011-03-31".

但是，如果我想在多年的季度周期内自动运行它，那将需要很长时间。

有没有办法将这种事情包装在一个查询中？

Answer 1

SELECT COUNT(DISTINCT user_id),YEAR(created_at), QUARTER(created_at)
FROM transactions 
GROUP BY YEAR(created_at), QUARTER(created_at)

Answer 2

这会满足你的要求吗？

select user_id, year(created_at) as `year`, quarter(created_at) as `quarter`, count(*)
from transactions
group by user_id, year(created_at), quarter(created_at)

Answer 3

像这样的东西怎么样：

SELECT COUNT(DISTINCT USER_ID), 
       QUARTER(created_at), 
       YEAR(created_at)    
  FROM transactions   
GROUP BY YEAR(created_at), QUARTER(created_at);