分析函数的高级SQL功能介绍
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2024-01-16 22:33:28
分析函数提供一系列比较高级的sql功能。分析函数是建立再数据窗口(over再一定范围进行数据分析),再一定的数据范围进行排序,汇总等.
查询当前员工所在部门的平均工资,最高工资和最低工资,即可通过分...
分析函数提供一系列比较高级的sql功能。分析函数是建立再数据窗口(over再一定范围进行数据分析),再一定的数据范围进行排序,汇总等.
查询当前员工所在部门的平均工资,最高工资和最低工资,即可通过分析函数来实现。
select e.last_name,e.salary,d.department_name, avg(e.salary) over(partition by d.department_name) department_avg_salary, max(e.salary) over(partition by d.department_name) department_avg_salary, min(e.salary) over(partition by d.department_name) department_avg_salary from employees e,departments d where 1 = 1 and e.department_id = d.department_id;
将一个部门内的员工的工资从高到低进行排序,注意三种排序结果是不一样的。
select d.department_name,e.last_name,e.salary, rank() over(partition by d.department_name order by e.salary desc) dept_salary_rank1, dense_rank() over(partition by d.department_name order by e.salary) dept_salary_rank2, row_number() over(partition by d.department_name order by e.salary) dept_salary_rank3 from employees e,departments d where 1 = 1 and e.department_id = d.department_id;