sql - 如何在 TSQL 中对产品进行分组，然后按日期 desc 对它们进行排序？

Question

这是SQL，但它给了我一个错误：

select u.productId, count(ProductID) as total, p.Name 
from dbo.UserXProduct AS u 
INNER JOIN dbo.product AS p ON u.ProductID = p.ID   
group by productid, p.name 
having count(ProductID) > 5 
order by u.dateEntered desc, total desc

编辑：这是我得到的错误：

列“dbo.UserXProduct.DateEntered”在 ORDER BY 子句中无效，因为它不包含在聚合函数或 GROUP BY 子句中

Answer 1

您不能u.dateEntered直接订购。但是，您可以按max(u.dateEntered). 这可能是您想要的最新产品：

select u.productId, count(ProductID) as total, p.Name 
from dbo.UserXProduct AS u 
INNER JOIN dbo.product AS p ON u.ProductID = p.ID   
group by productid, p.name 
having count(ProductID) > 5 
order by max(u.dateEntered) desc, total desc

Answer 2

您不能在group by. 试试这个：

select u.productId, count(ProductID) as total, p.Name 
from dbo.UserXProduct AS u 
INNER JOIN dbo.product AS p ON u.ProductID = p.ID   
group by productid, p.name 
having count(ProductID) > 5 
order by count(ProductID) desc

您不能ORDER BY使用 u.dateEntered 列，除非它存在于group by.