查找客户一起购买但不重复的产品列

Question

我正在使用 SQL 服务器，我试图找出一起购买最多的前 2 种产品

这是一个产品table

我希望它显示如下图：

我试过了

SELECT TOP 2 Product_Id, bought_with_Product_Id, times_bought_together 
FROM PRODUCT
GROUP BY Product_Id, bought_with_Product_Id, times_bought_together

也试过了

SELECT TOP 2 *
FROM Product
WHERE times_bought_together = (SELECT MAX(times_bought_together) FROM product)
AND Product_Id <> bought_with_Product_Id

它returns

如何才能使 product_id 和 bought_with_product_Id 行不重叠

Answer 1

您可以使用 NOT EXISTS 测试排除重复行，例如

declare @Test table (id int, otherId int, times int);

insert into @Test (id, otherId, times)
values
(1,2,3),
(2,1,3),
(4,1,2),
(1,4,2),
(1,5,1),
(5,1,1);

select top 2 *
from @Test T1
where not exists (
    select 1
    from @Test T2
    where T1.id = T2.otherId
    and T1.otherId = T2.id
    -- Keep the duplicate with the lower id
    and T2.id < T1.id
);

Returns:

id	otherId	times
1	2	3
1	4	2

注意：为您的测试数据提供 DDL+DML（如此处所示）可以让人们更容易回答您的问题。

查找客户一起购买但不重复的产品列

Find Products customer bought together but non repeating columns

sql

tsql

sql-server

duplicates