oracle sql查询第二个最大列表

Question

我有一份employee_sale表

id  product   quantity
3    y        6
1    x        2
1    y        5
2    x        4
3    x        3
3    y        5
3    X        5
4    y        3
4    y        4

我想选择所有产品的员工ID，产品和第二最大数量列表。

请帮助必要的SQL查询

感谢

Answer 1

我会使用rank()函数：

SELECT id, product, quantity
FROM   (SELECT id, product, quantity, 
               RANK() OVER (PARTITION BY id, product ORDER BY quantity DESC) 
               AS rk
        FROM   employee_sale)
WHERE  rk = 2

Answer 2

两种选择：

1. 使用ROW_NUMBER()：

   SELECT id,product,quantity FROM
   (SELECT *,ROW_NUMBER() OVER(PARTITION BY product ORDER BY quantity DESC) as RN
   FROM employee_sale) T
   WHERE RN=2
   

2. 使用RANK()：

   SELECT id,product,quantity FROM
   (SELECT *, RANK() OVER (PARTITION BY product ORDER BY quantity DESC) as Rnk
   FROM employee_sale) T
   WHERE Rnk=2
   

结果：

ID  PRODUCT  QUANTITY
2   x        4
1   y        5