博客

27、显示各种职位的最低工资(组函数)

select MIN(SALARY)  from employees  GROUP BY DEPARTMENT_ID

28、求1997年各个月入职的的员工个数(考察知识点:组函数)

select count(*) from employees  GROUP BY HIRE_DATE between '1997-01-01' and '1997-12-31'

29、查询每个部门的最高工资(考察知识点:分组)

select MAX(SALARY)  from employees  GROUP BY DEPARTMENT_ID

30、查询每个部门,每种职位的最高工资(考察知识点:分组)

select MAX(jobs.MAX_SALARY) from employees RIGHT JOIN jobs ON employees.JOB_ID=jobs.JOB_ID GROUP BY DEPARTMENT_ID

31、查询各部门的总工资

select SUM(SALARY) from employees  GROUP BY DEPARTMENT_ID