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题解 | 更新员工信息表

SELECT t1.EMPLOYEE_ID, IF ( UPDATE_DT > LAST_UPDATE_DT, NEW_POSITION, POSITION ) AS POSITION, IF ( ...

2025-04-29

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题解 | 未下单用户登陆渠道统计

select channel, count(*) as cnt from user_info u left join order_log o on u.uid = o.uid where order_id is null group by channe...

2025-04-29

2 64

题解 | 未下单用户统计

来，梳理一下清晰的思考过程：【1】明确需求：user_info表是所有注册用户。order_log表是有下过订单的记录。需要找出那些注册了，但从来没在order_log下过单的用户。结果是返回一个数量：cnt。【2】解题思路：用左连接（LEFT JOIN），并筛选右表(order_log)为空的数据...

2025-04-29

1 75

题解 | 输出播放量最高的视频

【1】明确需求：最大播放量：指某个视频在某个时刻，有多少条记录（多少用户）同时在观看它。Top3：找出最大播放量最大的前三个视频。保留三位小数。【2】解决思路整体：因为每个播放记录有 start_time 和 end_time，所以：✅ 如果某个时刻落在 start_time <= 时刻 &l...

2025-04-28

4 123

题解 | 每个顾客购买的最新产品名称

select customer_id, customer_name, product_name as latest_order from ( select o.customer_id, c.custome...

2025-04-28

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题解 | 各个部门实际平均薪资和男女员工实际平均薪资

SELECT department, ROUND(AVG(actual_salary), 2) AS average_actual_salary, ROUND( IFNULL( AVG(CASE WHEN staff_gender =...

2025-04-28

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题解 | 统计每个产品的销售情况

#顾客年龄分层并查询购买数量最多顾客 with t1 as (select c.customer_id, customer_name, product_id, case ...

2025-04-24

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题解 | 每个顾客最近一次下单的订单信息

select order_id, customer_name, order_date from ( select order_id, customer_name, order_da...

2025-04-22

0 50

题解 | 查询订单

select aa.order_id, aa.customer_name, aa.order_date from ( select o.order_id, c.customer_name, ...

2025-04-22

0 63

题解 | 每个部门薪资排名前两名员工

select department,employee_name,salary from( select department,employee_name,salary,row_number() over (partition by department order by department des...

2025-04-22

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