mysql - mysql select语句中的子查询

我正在尝试编写一个查询，其中按用户使用的促销代码对用户进行排序，并告诉我其中有多少人有免费计划，有多少人有付费计划。这是我的尝试。

select count(refer) as promo, (count(plan)
    from users
    where plan = 'free'
) as free, (count(plan)
    from users
    where plan <> 'free'
) as pay from users
where refer <> ''
group by refer

这是行不通的，但是我不确定要进行哪些更改才能使其正常工作。

最佳答案

通过功能CASE可以

select count(refer) as promo,
count(case when plan = 'free' then 1 end) as free
count(case when plan <> 'free' then 1 end) as pay
from users
where refer <> ''
group by refer

关于mysql - mysql select语句中的子查询，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/46458220/