MySQL初学笔记（第二次作业）
1.将员工表中的first_name、last_name进行拼接，将拼接的结果全部小写，按结果的首字母进行升序排序，显示最后拼接的姓名以及首字母
select CONCAT(LOWER(first_name),'_',LOWER(last_name)) 姓名,SUBSTR(first_name,1,1) 首字母
from employees
order by SUBSTR(first_name,1,1)
2.查询员工表中的入职日期按****年月日的格式进行显示
select employee_id,last_name,STR_TO_DATE(hiredate,'%Y-%c-%d') as 入职日期
from employees
3.查询员工工资、员工姓名、员工工资等级，结果按照员工工资升序排列
a)2000~5000为A等级
b)5001~8000为B等级
c)8001~10000为C等级
d)否则为D等级
select salary,last_name,case
when salary BETWEEN 2000 AND 5000 then 'A'
when salary BETWEEN 5001 AND 8000 then 'B'
when salary BETWEEN 8001 AND 10000 then 'C'
else 'D'
end 等级
from employees
order by salary asc
4.查询员工表中每个部门的最高工资小于8000的姓名、部门及最高工资
select last_name,department_id,max(salary)
from employees
where salary<8000
group by department_id
5.查询员工姓名为Faviet对应的部门名以及部门所在街区信息
select last_name,department_name,street_address
from employees e
inner join departments d
on e.department_id = d.department_id
inner join locations l
on d.location_id = l.location_id
where last_name = 'Faviet'