购买每件商品的顾客

Question

我正在尝试构建一个查询，该查询将向我显示购买所有商品的客户列表。

我想也许 unique 和 EXISTS 选项或者 count() 可能是一个解决方案，但我不确定如何将这一切放在一起。任何帮助将不胜感激。

下面是我的示例数据和预期输出。

CREATE TABLE customers (CUSTOMER_ID, FIRST_NAME, LAST_NAME) AS 
SELECT 1, 'Abby', 'Katz' FROM DUAL UNION ALL
SELECT 2, 'Lisa', 'Jones' FROM DUAL UNION ALL 
SELECT 3, 'Joanne','Dalton' FROM DUAL; 

CREATE TABLE items (PRODUCT_ID, PRODUCT_NAME) AS 
SELECT 100, 'Black Shoes' FROM DUAL UNION ALL
 SELECT 101, 'Brown Shoes' FROM DUAL UNION ALL
SELECT 102, 'White Shoes' FROM DUAL; 

CREATE TABLE purchases (CUSTOMER_ID, PRODUCT_ID, QUANTITY, PURCHASE_DATE) AS
SELECT 1, 100, 1, TIMESTAMP'2024-05-11 09:54:48' FROM DUAL UNION ALL
SELECT 1, 101, 1, TIMESTAMP'2024-05-11 19:54:48' FROM DUAL UNION ALL
SELECT 1, 102, 1, TIMESTAMP'2024-06-09 14:54:48' FROM DUAL UNION ALL
SELECT 3, 100, 1, TIMESTAMP'2024-06-09 11:34:44' FROM DUAL UNION ALL
SELECT 3,102,1, TIMESTAMP '2024-05-10 19:04:18' FROM DUAL;

CUSTOMER_ID FIRST_NAME LAST_NAME DISTINCT_ITEM_CNT

1 Abby Katz 3

Answer 1

您可以使用

PARTITION

ed

OUTER JOIN

来生成计数：

SELECT c.*,
       p.distinct_item_cnt
FROM   customers c
       INNER JOIN (
         SELECT customer_id,
                COUNT(DISTINCT p.product_id) AS distinct_item_cnt
         FROM   items i
                LEFT OUTER JOIN purchases p
                PARTITION BY (p.customer_id)
                ON (p.product_id  = i.product_id)
         GROUP BY p.customer_id
         HAVING COUNT(DISTINCT p.product_id) = COUNT(i.product_id)
       ) p
       ON p.customer_id = c.customer_id

对于样本数据，输出：

CUSTOMER_ID	FIRST_NAME	LAST_NAME	DISTINCT_ITEM_CNT
1	艾比	卡兹	3

小提琴