Question

我的代码

select 
    (select ifnull(sum(registerAmount),0) 
     from register where register.orderID = orders.orderID) as theTotal 
from orders 
left join register on orders.orderID = register.orderID 
where orders.customerID = 17 and invSent = true

显示8行... 5包含0而3则不包含。

如果我添加

group by orders.customerID

我得到一行包含零。

如何获得包含总数的一行？

Answer 1

如果你只想要一行包含所有内容，只需做一个简单的INNER JOIN并选择总和。

SELECT IFNULL(SUM(registerAmount), 0) as theTotal
FROM orders
INNER JOIN register ON orders.orderID = register.orderID
WHERE orders.customerID = 17 and invSent = true

通过查询简单（？）MySQL组

1 个答案: