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假设有以下数据表"orders"（order_id为主键），

[不定项选择题]

假设有以下数据表"orders"（order_id为主键），记录了订单的信息：

order_id	customer_id	order_date	amount
1	1001	2022-01-01	100
2	1002	2022-01-02	150
3	1001	2022-01-03	200
4	1003	2022-01-04	120

请选出查询语句，找出每个顾客的订单数量，以及该顾客的第一笔订单的日期（）

SELECT customer_id, COUNT(order_id) as order_count, MIN(order_date) as first_order_date FROM orders GROUP BY customer_id;

SELECT customer_id, COUNT(*) as order_count, MIN(order_date) as first_order_date FROM orders GROUP BY customer_id;

ELECT customer_id, COUNT(order_id) as order_count, order_date as first_order_date FROM orders GROUP BY customer_id ORDER BY order_date ASC;

SELECT customer_id, COUNT(order_id) as order_count, MAX(order_date) as first_order_date FROM orders GROUP BY customer_id;

查看答案及解析

一笑而过2222

选项A用 COUNT(order_id) 统计订单数、 MIN(order_date) 取最早订单日期并按 customer_id 分组，选项B用 COUNT(*) 统计订单数且聚合、分组逻辑与A一致，二者均符合需求；选项C未对 order_date 聚合且违反分组规则，选项D用 MAX(order_date) 错误获取最晚日期，因此正确答案是A、B。

发表于 2025-12-17 07:25:43 回复(0)