mysql - 基于内部选择的计数

Question

我想根据子选择语句进行计数。

SELECT MONTH(Received), State, COUNT('id'), SUM(price) FROM Leads GROUP BY MONTH(Received), State

该查询有效并生成类似这样的内容

MONTH(Received)     State   COUNT('id')    SUM(price)
4                   CA      25             35
4                   UT      13             8

我要计算的是有多少行的价格 > 0

这是我试过的查询

SELECT MONTH(Received), SUM(price), COUNT(`id`), (SELECT COUNT(*) as count FROM Leads WHERE Price > 0) as NumPaidLeads, State FROM Leads GROUP BY MONTH(Received), State

但是NumPaidLeads统计整列，价格列是数字类型。

我做错了什么？

Answer 1

在您的案例中，如果要计算价格 > 0 的行数，您可以使用一个案例

SELECT MONTH(Received), State, 
 sum( case when price > 0 then 1 else 0 END) num_row_with_price, SUM(price) 
FROM Leads 
GROUP BY MONTH(Received), State