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全部文章（共49篇）

题解 | 查询成绩

SELECT count(*) FROM ( SELECT AVG(SC.score) FROM SC INNER JOIN Course AS c ON SC.cId = c.c...

2025-09-02

1 26

题解 | 电商平台需要对商品的销售和评价情况进行综合分析

WITH avg_product AS( SELECT p.product_id, p.product_name, ROUND(AVG(r.rating),2) AS average_rating FROM produc...

2025-08-25

1 28

题解 | 评估不同供应商提供的零部件质量和成本情况

SELECT s.supplier_id, s.supplier_name, c.component_name, sq.quality_score, sq.cost FROM suppliers AS s INNER JOIN supp...

2025-08-25

0 22

题解 | 用户订单信息查询

SELECT c.city, SUM(o.total_amount) AS total_order_amount FROM orders AS o INNER JOIN customers AS c ON o.customer_id=c.customer_id...

2025-08-25

1 29

题解 | 统计用户从访问到下单的转化率

SELECT vu.date, CONCAT(ROUND(ou.num/vu.num*100,1),'%') AS cr FROM #算每天访问的人数 (SELECT DATE(visit_time) AS date, COUNT(DISTINCT user_id) ...

2025-08-24

1 22

题解 | 对所有员工的薪水按照salary降序进行1-N的排名

#题目很简单，那个1-N是从1到N的意思，不是1减N的意思；开始以为是1减N，百思不得其解，不知道题目想干啥 SELECT emp_no, salary, DENSE_RANK() OVER (ORDER BY salary DESC) AS t_rank FROM ...

2025-08-23

0 33

题解 | 获得积分最多的人(一)

SELECT u.name, SUM(g.grade_num) AS grade_num FROM user AS u INNER JOIN grade_info AS g ON u.id=g.user_id GROUP BY u.name ORDER...

2025-08-23

1 22

题解 | 将所有获取奖金的员工当前的薪水增加10%

UPDATE salaries SET salary=salary*1.1 WHERE to_date='9999-01-01' AND emp_no IN ( SELECT emp_no FROM em...

2025-08-23

1 24

题解 | 分析员工在不同项目中的绩效表现以及所属部门的平均绩效情况

WITH department_stats AS ( SELECT ep.employee_id, di.department_name, ep.performance_score, AVG(ep.performance_sc...

2025-08-22

1 39

题解 | 饿了么需要分析不同配送员在不同天气条件下的配送效率和用户投诉情况

#先找出符合条件的配送员 WITH satff_filter AS ( SELECT staff_id FROM ( SELECT ds.staff...

2025-08-22

1 37