MySQL大神进阶挑战:那些让人拍案叫绝的数据库问题与答案!,想知道如何在MySQL的海洋里游刃有余吗?来吧,让我们一起解开那些困扰数据库达人们的难题,看看这些高手们的巧妙解答!🏆📚
```sqlSELECT e.employee_id, e.position, MAX(s.salary) as highest_salaryFROM employees eJOIN salaries s ON e.employee_id = s.employee_idGROUP BY e.employee_id, e.position;```答案:利用JOIN和GROUP BY,轻松找出每位员工的最高薪资及其职位。
```sqlSELECT u.user_id, COUNT(*) OVER (PARTITION BY u.user_id) as purchase_countFROM users uJOIN orders o ON u.user_id = o.user_idWHERE o.order_date BETWEEN DATE_SUB(CURDATE(), INTERVAL 1 YEAR) AND CURDATE()AND o.refund_status = 0;```答案:使用窗口函数COUNT和时间范围筛选条件,找出符合条件的用户。
```sqlSELECT d.department_name, AVG(s.salary) as avg_salaryFROM departments dJOIN salaries s ON d.department_id = s.department_idGROUP BY d.department_nameORDER BY avg_salary DESC;```答案:利用JOIN和AVG函数,结合ORDER BY实现部门薪资排名。
```sqlSELECT p.product_id, p.product_name, SUM(o.quantity) as total_salesFROM products pJOIN orders o ON p.product_id = o.product_idGROUP BY p.product_id, p.product_nameORDER BY total_sales DESCLIMIT 10;```答案:通过JOIN和SUM,展示销售数据的王者榜。
```sqlCREATE VIEW last_login_view ASSELECT u.user_id, MAX(l.login_date) as last_loginFROM users uJOIN login_history l ON u.user_id = l.user_idGROUP BY u.user_id;```答案:创建视图,轻松跟踪用户最新登录记录。
以上只是冰山一角,真正的MySQL大神还在不断探索更复杂的查询技巧。记得,实践是检验真理的唯一标准,多做题,多思考,你也可以成为下一个MySQL数据库的传奇!🚀👨💻现在,你准备好迎接下一个挑战了吗?让我们一起在MySQL的世界里,挖掘更多的知识宝藏吧!🔍🌟