如何标记SQL Server中表/列中​​的重复值？

Question

我有一个表，它是3个表的连接，显示以下信息。

|| OrderID || Order Date || Customer || Customer City || Product || Amount ||

如果客户在同一天订购的产品超过一次，我希望另一列为|| Dual Purchase ||？

值应为YES或NO

因此，如果John于6月16日以2个单独的顺序购买可口可乐，那么对两个订单ID都应该YES

Answer 1

你可以这样做：

SELECT OrderID 
    , OrderDate
    , Customer 
    , CustomerCity
    , Product 
    , Amount 
    , Case when Count(Product) Over(Partition by OrderDate, Customer, Product) > 1 
        then 'Yes' else 'No' end as DualPurchase
FROM TableName

Answer 2

使用窗口功能ROW_NUMBER()按OrderID和Customer定义双重记录。检查，如果行大于1：

DECLARE @Table TABLE (OrderID int, Customer  int, OrderDate date)

INSERT INTO @Table 
VALUES
(1,2, Getdate()),
(1,2, DATEADD(day,1,Getdate())),
(1,2, DATEADD(day,1,Getdate())),
(2,3, Getdate()),
(2,3, DATEADD(day,1,Getdate()))

SELECT 
    *,
    IIF(ROW_NUMBER() OVER (PARTITION BY t.OrderID, t.Customer ORDER BY t.OrderID) > 1, 'YES', 'NO') AS DualPurchase
FROM @Table AS t

Answer 3

我认为这会对你有帮助..

Select
            O.OrderID,O.[Order Date],c.Customer,c.[Customer City],P.Product,O.Amount,a.[More then Once]
from        Orders O
inner join  Customers C
on          O.Customer_Id=C.Customer_Id
inner join  Product P
On          O.Product_Id=P.Product_Id
Cross Apply (   select Case when count(1)>1 then 'Yes' Else 'No' [More then Once] end from Orders
                where Customer_Id=O.Customer_Id and cast([Order Date] as date)=cast(O.[Order Date] as date)
                group by Customer_Id,cast([Order Date] as date)
            ) a