1.背景:作为一名测试工程师,sql语句也是必备技能,刚好前两天朋友的面试题做为列子简单做下笔记
2.question:
3.answer:
1)update employee set salary=salary+200 where age>=40 and salary<2000
2)select distinct depart.name,count(depart.id) as m from depart ,employee,DE where employee.ID=DE.eid and depart.id=DE.did and employee.age>=40 and employee.salary<2200 GROUP BY(depart.name) order by m
4.提示:个人觉得sql语句并不难,格外要注意的是各个语句的执行顺序,推荐大家看下这篇博客写的很详细
https://www.cnblogs.com/ghost-xyx/p/3811036.html
~还有左联、外联、跨表联