表: Customer
+---------------+---------+ | Column Name | Type | +---------------+---------+ | customer_id | int | | customer_name | varchar | +---------------+---------+ customer_id 是该表主键. 该表的每行包含网上商城的每一位顾客的信息.
表: Orders
+---------------+---------+ | Column Name | Type | +---------------+---------+ | order_id | int | | sale_date | date | | order_cost | int | | customer_id | int | | seller_id | int | +---------------+---------+ order_id 是该表主键. 该表的每行包含网上商城的所有订单的信息. sale_date 是顾客customer_id和卖家seller_id之间交易的日期.
表: Seller
+---------------+---------+ | Column Name | Type | +---------------+---------+ | seller_id | int | | seller_name | varchar | +---------------+---------+ seller_id 是该表主键. 该表的每行包含每一位卖家的信息.
写一个SQL语句, 报告所有在2020年度没有任何卖出的卖家的名字.
返回结果按照 seller_name 升序排列.
查询结果格式如下例所示.
示例 1:
输入： Customer表: +--------------+---------------+ | customer_id | customer_name | +--------------+---------------+ | 101 | Alice | | 102 | Bob | | 103 | Charlie | +--------------+---------------+Orders表: +-------------+------------+--------------+-------------+-------------+ | order_id | sale_date | order_cost | customer_id | seller_id | +-------------+------------+--------------+-------------+-------------+ | 1 | 2020-03-01 | 1500 | 101 | 1 | | 2 | 2020-05-25 | 2400 | 102 | 2 | | 3 | 2019-05-25 | 800 | 101 | 3 | | 4 | 2020-09-13 | 1000 | 103 | 2 | | 5 | 2019-02-11 | 700 | 101 | 2 | +-------------+------------+--------------+-------------+-------------+Seller表: +-------------+-------------+ | seller_id | seller_name | +-------------+-------------+ | 1 | Daniel | | 2 | Elizabeth | | 3 | Frank | +-------------+-------------+输出：+-------------+ |seller_name| +-------------+ | Frank | +-------------+解释：Daniel在2020年3月卖出1次. Elizabeth在2020年卖出2次, 在2019年卖出1次. Frank在2019年卖出1次, 在2020年没有卖出.