mysql - 用户如何使用左联接聚合功能？ MySQL的

我有这样的疑问：

SELECT business.bussId, COUNT(invoices.userId) as invoices, COUNT(rating.bussId) as ratingCount ,
       FROM business
       LEFT JOIN invoice ON (invoice.bussId = business.bussId AND invoice.userId = '3000' )
       LEFT JOIN rating ON (rating.bussId = business.bussId )
       WHERE business.bussId=100

COUNT（invoices.userId）用户应该返回invoices表中的行数，其中userId=3000，bussId=100。
换句话说，这个查询：

SELECT COUNT(*) as invoice FROM `invoices` WHERE bussId = '100' AND userId = '30000'.

第二个查询返回COUNT（*）=3，第一个查询（当用户离开JOIN时）返回15，如何修复？

最佳答案

尝试以下查询：

SELECT business.bussId, (select count(invoices.userId) from invoice where invoice.bussId = a.bussId AND invoice.userId = '3000' ) as invoices, (select COUNT(rating.bussId) from rating where rating.bussId = a.bussId ) as ratingCount ,
       FROM business a
              WHERE business.bussId=100