row_number() over(partition by... order by...)分组聚合排序

row_number() over(partition by... order by...)分组聚合排序

ROW_NUMBER() OVER(
    [PARTITION BY column_1, column_2,…]
    [ORDER BY column_3,column_4,…] [desc/asc]
)

PARTITION BY 分组通过
ORDER BY 排序通过

sqlserver用法示例

创建表

use dbo;
IF object_id('employee') is not null drop table employee;

create table employee(employee int, departid int,salary decimal(18,2));

insert into employee values(1,10,5500.00);
insert into employee values(2,10,4500.00);
insert into employee values(3,20,1900.00);
insert into employee values(4,20,4800.00);
insert into employee values(5,40,6500.00);
insert into employee values(6,40,14500.00);
insert into employee values(7,40,44500.00);
insert into employee values(8,50,6500.00);
insert into employee values(9,50,7500.00);

select * from employee;

employee	departid	salary
1	10	5500.00
2	10	4500.00
3	20	1900.00
4	20	4800.00
5	40	6500.00
6	40	14500.00
7	40	44500.00
8	50	6500.00
9	50	7500.00

先分组再排序（先排序partition by后面的，再排序order by后面的）

select
  employee
  ,departid
  ,salary
  ,row_number() over(partition by departid order by salary) sno
from employee

结果

employee	departid	salary
2	10	4500.00
1	10	5500.00
3	20	1900.00
4	20	4800.00
5	40	6500.00
6	40	14500.00
7	40	44500.00
8	50	6500.00
9	50	7500.00