oracle学习79-oracle之单行函数之分组函数

 

 

    --分组函数
    select avg(salary),max(salary),min(salary),sum(salary) from employees

运行结果

     
    --判断大小
    select max(last_name),min(last_name),max(hire_date),min(hire_date) from employees

 运行结果

    --计数
    select count(employee_id),count(last_name),count(hire_date) from employees

运行结果

    --求平均值
    select avg(salary),sum(salary)/count(salary) from employees;

运行结果

     
    --计算不为空
    select count(commission_pct) from employees

运行结果

    --
    select count(distinct department_id) from employees

    --查出员工表里面的平均工资
    select department_id,avg(salary)
    from employees
    group by department_id

运行结果

    --查出员工表里面的平均工资
    select department_id,job_id,avg(salary)
    from employees
    group by department_id,job_id

运行结果

    --查出员工表里面的平均工资大于6000 以及平均工资
    select department_id,avg(salary)
    from employees
    having avg(salary)>6000
    --where department_id in (40,60,80)
    group by department_id