SQL 计算产品相同的客户

Question

我有问题。我有一个名为 customers 的 SQL 数据库，其中包含 3 列 Country、CustomerID 和 Product。使用该数据库，我想计算购买自行车、烧瓶和头盔产品但按国家/地区分组的所有客户，如下图所示。

你能帮我解决这个问题吗？我想我必须在同一个表上进行连接并使用另一个选择进行嵌套查询，但我真的不知道该怎么做。

非常感谢您的帮助！

Answer 1

您可以将 HAVING 子句与 GROUP BY 一起使用，同时在对这三种产品进行计数后对每个客户进行明确计数，例如

SELECT Country, COUNT(DISTINCT CustomerID) AS Count 
  FROM customers 
 WHERE Product IN ('Bike','Flask','Helmet') 
   AND CustomerID IN ( SELECT CustomerID 
                         FROM customers 
                        GROUP BY CustomerID 
                       HAVING COUNT(DISTINCT Product)=3 )
 GROUP BY Country

Demo

Answer 2

您必须分两步进行聚合。首先找到拥有 3 种不同产品的客户，然后统计这些客户。

SELECT country, count(*)
FROM
(
  SELECT country, CustomerID 
  FROM customers 
  WHERE product IN ('Bike','Flask','Helmet') 
  GROUP BY country, CustomerID
  HAVING COUNT(distinct product) = 3
) dt
GROUP BY country

Answer 3

试试这个sql：

select Country,count(distinct CustomerID) 
from customers 
where Product in ('Bike','Flask','Helmet') 
group by Country

Answer 4

选择国家，计数（不同的客户ID） 来自客户 产品在 ('Bike','Flask','Helmet') 按国家分组

Answer 5

SELECT COUNT(CustomerID), Country
FROM Customers
GROUP BY Country
HAVING Product in ('Bike','Flask','Helmet');