SQL选择CTE

Question

我想要做的就是获得订单数量最多的城市名称。看起来很简单，但是当我运行这个代码时（我不得不使用CTE），我只得到订单数量，没有城市名称。

WITH CityOrder AS
(
    SELECT City 
    FROM Person.Address JOIN Sales.SalesOrderHeader 
        ON ShipToAddressID = AddressID
), 
CitiesOrders AS
(
    SELECT City, COUNT(City) AS "NoOfOrders"
    FROM CityOrder
    GROUP BY City
)
SELECT MAX("NoOfOrders") FROM CitiesOrders;

我尝试将最后一行更改为

SELECT City, MAX("NoOfOrders") FROM CitiesOrders;

然而，它显示了所有城市的订单。我很确定我没有看到一些简单的错误。有什么建议？

Answer 1

订购您的结果并获得前1名，但如果有几个城市的订单数相同，则会有关系：

...
SELECT TOP 1 WITH TIES * 
FROM CitiesOrders
ORDER BY NoOfOrders DESC

Answer 2

试试这个！

select top 1 * from
(
SELECT City,count(1) as x 
    FROM Person.Address JOIN Sales.SalesOrderHeader 
        ON ShipToAddressID = AddressID
group by City
) order by x desc

Answer 3

WITH CityOrder AS
(
SELECT City 
    FROM Person.Address JOIN Sales.SalesOrderHeader 
    ON ShipToAddressID = AddressID
),  
CitiesOrders AS
(
SELECT City, COUNT(City) AS "NoOfOrders"
    FROM CityOrder
   GROUP BY City
)
SELECT * from CitiesOrders order by "NoOfOrders" desc limit 1;

Answer 4

你写的是完美的查询，但有一点缺失。您可以将查询与Group by一起使用。

SELECT City, MAX("NoOfOrders") FROM CitiesOrders group by City