mysql - MySQL在不同的查询中选择总计

Question

我想获得每个客户（公司）的交易总数。如何在此查询中添加一个计数器来计算每个公司的事务表中的记录数？

select DISTINCT c.CompanyName, c.ContactEmail
From Transactions tr
JOIN Tenants t on tr.tenantid = t.tenantid
JOIN Properties p on t.propertyid = p.propertyid
JOIN Company c on c.companyid = p.companyid

谢谢

标签： mysqlsql

Answer 1

使用GROUP BY：

SELECT c.CompanyName, c.ContactEmail, COUNT(*)
FROM Transactions tr JOIN
     Tenants t ON tr.tenantid = t.tenantid
     Properties p ON t.propertyid = p.propertyid
     Company c ON c.companyid = p.companyid
GROUP BY c.CompanyName, c.ContactEmail;