如何获取与分组集中到不同列中的最小值和最大值对应的项目的名称

Question

表 1 ：订单（ORDER_ID、CUSTOMER_ID、ITEM_ID、QUANTITY）

表 2 ：客户（CUSTOMER_ID、CUSTOMER_NAME、ZIPCODE）

表 3 ：项目（ITEM_ID，ITEM_NAME）

所需输出：输出（邮政编码、MAX_ORDERED_ITEM_NAME、MIN_ORDERED_ITEM_NAME

我尝试了各种方法来获得输出，但一直无法得到最终结果

当前查询：

SELECT ZIPCODE, ITEM_NAME, SUM(QUANTITY) AS SALES
FROM ORDERS
JOIN CUSTOMERS ON ORDERS.CUSTOMER_ID = CUSTOMERS.CUSTOMER_ID
JOIN ITEMS ORDERS.ITEM_ID = ITEMS.ITEM_ID
GROUP BY ZIPCODE, ITEM_NAME
ORDER BY SALES DESC;

Answer 1

您可以group by以下方式对group by使用分析函数ROW_NUMBER ：

 SELECT O.ZIPCODE, MAX(CASE WHEN MAXRN = 1 THEN ITEM_NAME END) AS MAX_ORDERED_ITEM_NAME, MAX(CASE WHEN MINRN = 1 THEN ITEM_NAME END) AS MIN_ORDERED_ITEM_NAME FROM (SELECT O.ZIPCODE, I.ITEM_ID, I.ITEM_NAME, ROW_NUMBER() OVER (PARTITION BY I.ITEM_ID ORDER BY SUM(QUANTITY) ) AS MINRN, ROW_NUMBER() OVER (PARTITION BY I.ITEM_ID ORDER BY SUM(QUANTITY) DESC NULLS LAST) AS MAXRN FROM ORDERS O JOIN ITEMS I ON I.ITEM_ID = O.ITEM_ID JOIN CUSTOMERS C ON C.CUSTOMER_ID = O.CUSTOMER_ID GROUP BY O.ZIPCODE, I.ITEM_ID, I.ITEM_NAME) WHERE 1 IN (MINRN, MAXRN) GROUP BY O.ZIPCODE;

干杯！！