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MySQL - ROW_NUMBER() OVER()函数用法详解(分组排序)


语法格式:row_number() over(partition by 分组列 order by 排序列 desc)

row_number() over()分组排序功能:

在使用 row_number() over()函数时候,over()里头的分组以及排序的执行晚于 where 、group by,但不晚于 order by 的执行。

案例

表数据

create table TEST_ROW_NUMBER_OVER(
id varchar(10) not null,
name varchar(10) null,
age varchar(10) null,
salary int null
);
select * from TEST_ROW_NUMBER_OVER t;

insert into TEST_ROW_NUMBER_OVER(id,name,age,salary) values(1,'a',10,8000);
insert into TEST_ROW_NUMBER_OVER(id,name,age,salary) values(1,'a2',11,6500);
insert into TEST_ROW_NUMBER_OVER(id,name,age,salary) values(2,'b',12,13000);
insert into TEST_ROW_NUMBER_OVER(id,name,age,salary) values(2,'b2',13,4500);
insert into TEST_ROW_NUMBER_OVER(id,name,age,salary) values(3,'c',14,3000);
insert into TEST_ROW_NUMBER_OVER(id,name,age,salary) values(3,'c2',15,20000);
insert into TEST_ROW_NUMBER_OVER(id,name,age,salary) values(4,'d',16,30000);
insert into TEST_ROW_NUMBER_OVER(id,name,age,salary) values(5,'d2',17,1800);

一次排序:对查询结果进行排序(无分组)

select id,name,age,salary,row_number()over(order by salary desc) rn
from TEST_ROW_NUMBER_OVER t

结果

MySQL - ROW_NUMBER() OVER()函数用法详解(分组排序)_MySQL

进一步排序:根据id分组排序

select id,name,age,salary,row_number()over(partition by id order by salary desc) rank
from TEST_ROW_NUMBER_OVER t

结果

MySQL - ROW_NUMBER() OVER()函数用法详解(分组排序)_数据库_02

再一次排序:找出每一组中序号为一的数据

select * from(select id,name,age,salary,row_number()over(partition by id order by salary desc) rank
from TEST_ROW_NUMBER_OVER t)
where rank < 2

结果

MySQL - ROW_NUMBER() OVER()函数用法详解(分组排序)_MySQL_03

排序找出年龄在13岁到16岁数据,按salary排序

select id,name,age,salary,row_number()over(order by salary desc)  rank
from TEST_ROW_NUMBER_OVER t where age between '13' and '16'

结果:结果中 rank 的序号,其实就表明了 over(order by salary desc) 是在where age between and 后执行的

MySQL - ROW_NUMBER() OVER()函数用法详解(分组排序)_OVER_04


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