ROW_NUMBER() OVER函数的用法

语法：ROW_NUMBER() OVER(PARTITION BY COLUMN ORDER BY COLUMN)

partition 划分，分割

--ROW_NUMBER() 就是生成一个有顺序的行号,而他生成顺序的标准,就是后面紧跟的OVER(ORDER BY ID)

--还必须添加OVER语句以便告诉SQL Server你希望怎样添加行序号。

实例：初始化数据

create table school (id int,class varchar2(12),score decimal(10,2))
insert into school values (1,'yiban',85.00);
insert into school values (2,'yiban',90.00);
insert into school values (3,'yiban',72.00);
insert into school values (4,'erban',60.00);
insert into school values (5,'erban',83.00);
insert into school values (6,'erban',76.00);
insert into school values (7,'sanban',92.00);
insert into school values (8,'sanban',63.00);
insert into school values (9,'sanban',59.00);
insert into school values (10,'sanban',77.00);
insert into school values (11,'siban',84.00)

数据显示为

需求：把所有同学的成绩按降序排列，再为降序后的每条记录返回一个序号

sql脚本：

select row_number()over(order by score desc) rank,score from school

数据显示为：

row_number() OVER (PARTITION BY COL1 ORDER BY COL2) 表示根据COL1分组，在分组内部根据 COL2排序，而此函数计算的值就表示每组内部排序后的顺序编号（组内是连续的唯一的)

需求：根据班级分组，显示每个班级的成绩成绩排名

sql脚本：

select row_number()over(partition by class order by score desc) rank ,id,class,score from school

数据显示为：