員工部門工資SQL面試題

現有employee 表，表中有 員工編號（id） 員工年齡（age） 員工工資（salary） 員工部門（deptid）, 按要求用一條SQL語句完成

create table employee(  
id int  identity(1,1) primary key ,  
name varchar(50),  
salary bigint,  
deptid int);

1.查出每個部門高於部門平均工資的員工名單

select ta.* from employee ta,  
(select deptid,avg(salary) avgsal from employee group by deptid)tb   
where ta.deptid=tb.deptid and ta.salary>tb.avgsal

2、列出各個部門中工資高於本部門的平均工資的員工數和部門號，並按部門號排序。

select ta.deptid,count(*) as ‘人數’  from employee ta,  
(select deptid,avg(salary) avgsal from employee group by deptid)tb   
where ta.deptid=tb.deptid and ta.salary>tb.avgsal group by ta.deptid order by ta.deptid

3.求每個部門工資不小於6000的人員的平均值；

SELECT avg(salary) as ‘平均值’,deptid FROM employee  where salary >=6000 GROUP BY dept_id

4、各部門在各年齡段的平均工資

select deptid,
sum(case when age < 20 then salary else 0 end) / sum(case when age <20 then 1 else 0 end) as “20歲以下平均工資”,
sum(case when age >= 20 and age <40 then salary else 0 end) / sum(case when age >= 20 and age <40 then 1 else 0 end) as “20至40歲平均工資”,
sum(case when age >= 40 then salary else 0 end) / sum(case when age >=40 then 1 else 0 end) as “>40歲及以上平均工資”,
from employee
group by deptid