SQL 列出所有人购买的商品

Question

关于如何在 SQL 中写这个有什么想法吗？

List all the customers who bought products bought by every other

架构是：

Customer (cId, cName)
Buys (tId, cId, pId)
Product (pId, pName)

我一直在尝试 select 所有不同的项目并使用它对 table 购买进行分组，但没有成功。

Answer 1

-- Customers who bought products bought by every other customer
SELECT DISTINCT cId,cName
  FROM Customer c1
      ,Buys b1
 WHERE c1.cId = b1.cId
   AND pId IN
-- Products bought by every other customer   
(SELECT pId
   FROM (SELECT pId,COUNT(1) count_p
          FROM (SELECT DISTINCT 
                       cId,pId
                  FROM Buys)
          GROUP BY pId) t1
       ,(SELECT COUNT(1) count_c
           FROM Customer) t2
  WHERE t1.count_p = t2.count_c)

试试上面的查询，看看它是否有效。我没有机会测试这个。

Answer 2

试试这个，在随机数据上测试，效果很好。在大量数据上可能会很慢..

SELECT cid, NAME
  FROM (SELECT c.cid, c.name, cc.cnt, COUNT(b.pid) cpid
          FROM customer c, buys b, product p, (SELECT COUNT(*) cnt FROM customer) cc
         WHERE c.cid = b.cid
           AND b.pid = p.pid
         GROUP BY c.cid, c.name, cc.cnt)
 WHERE cpid = cnt

Answer 3

您想要一份客户列表，这些客户只购买了所有客户购买的产品。所以我认为您应该在子查询中将所有产品标记为 SoldToAll 或不是。然后，您必须确定您的客户是否购买了至少一种标记为 SoldToAll = 1 的产品和标记为 SoldToAll = 0 的产品中的 none。

-- Step 1. Flag products as SoldToAll
SELECT 
    pid
    ,CASE COUNT(*) = (SELECT COUNT(*) FROM Customer) THEN 1 ELSE 0 END AS SoldToAll
FROM 
    (SELECT cid,pid 
    FROM buys 
    GROUP BY cid,pid
    ) CustProd
GROUP BY
    pid
-- Step 2. Use the above to get list
;WITH Prod AS 
    (SELECT 
        pid
        ,CASE COUNT(*) = (SELECT COUNT(*) FROM Customer) THEN 1 ELSE 0 END AS SoldToAll
    FROM 
        (SELECT cid,pid 
        FROM buys 
        GROUP BY cid,pid
        ) CustProd
    GROUP BY
        pid)
SELECT
    DISTINCT Buys.cid
FROM
    Buys
WHERE
    pid IN (SELECT pid FROM Prod WHERE SoldToAll = 1)
EXCEPT
SELECT
    DISTINCT Buys.cid
FROM
    Buys
WHERE
    pid IN (SELECT pid FROM Prod WHERE SoldToAll = 0)

SQL 列出所有人购买的商品

SQL list items bought by everyone

sql

oracle

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