MySQL开窗函数 - ToB企服应用市场:ToB评测及商务社交产业平台

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# 三种排序函数: row_number() rank() dense_rank()
# 数据准备
create table employee (
empid int,ename varchar(20) ,deptid varchar(10) ,salary decimal(10,2)
);
insert into employee values(1,'刘备','蜀',5500.00);
insert into employee values(2,'赵云','蜀',4500.00);
insert into employee values(3,'张飞','蜀',3500.00);
insert into employee values(4,'关羽','蜀',4500.00);
insert into employee values(5,'曹操','魏',1900.00);
insert into employee values(6,'许褚','魏',4800.00);
insert into employee values(7,'张辽','魏',6500.00);
insert into employee values(8,'徐晃','魏',14500.00);
insert into employee values(9,'孙权','吴',44500.00);
insert into employee values(10,'周瑜','吴',6500.00);
insert into employee values(11,'陆逊','吴',7500.00);
# 需求一: 使用三种排序函数对employee表中员工按照薪资进行降序排名：
select *,row_number() over (order by salary desc) as rank1,rank() over (order by salary desc)as rank2,dense_rank() over (order by salary desc)as rank3 from employee;
# 需求二: 对employee表中按照deptid进行分组，并对每一组的员工按照薪资进行降序排名：
select *,row_number() over (partition by deptid order by salary desc) as rank1,rank() over (partition by deptid order by salary desc)as rank2,dense_rank() over (partition by deptid order by salary desc)as rank3 from employee;
#开窗函数经常用于解决TOP N问题

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