如何从嵌套选择嵌套两个值？ MySQL的

Question

查询：

SELECT business.bussId, 
(select count(invoices.userId) from invoice where invoice.userId = '3000') 
as invoiceCount,  
(select SUM(invoices.price) from invoice where invoice.userId = '3000') 
as invoiceprice , 
FROM business WHERE business.bussId=100 

我怎么能拿使用发票价格和invoiceCount一个嵌套的选择？

Answer 1

移动子查询到from条款：

SELECT b.bussId, i.invoiceCount, i.invoiceprice 
FROM business b cross join 
    (select count(i.userId) as invoiceCount, SUM(i.price) as invoiceprice 
     from invoice i 
     where i.userId = '3000' 
    ) i 
WHERE b.bussId = 100; 

实际上，你可以写这个没有子查询，但你的问题是专门关于使用子查询。

这形式是：

SELECT b.bussId, count(i.userId) as invoiceCount, SUM(i.price) as invoiceprice 
FROM business b left join 
    invoice i 
    on i.userId = '3000' and b.bussId = 100 
GROUP BY b.bussId;