排名主要利用三种函数

• rank() 排序相同时重复，总数不会减少

• dense_rank() 排序相同时重复，总数减少

• row_number() 排序不重复，总数不变

比如对如下表根据分数进行降序排名

id	grade
1	97
2	96
3	95
4	95
5	98
6	94

rank()

id	grade	rank
5	98	1
1	97	2
2	96	3
3	95	4
4	95	4
6	94	6

select id, grade, rank() over(order by grade) as rank from data_table

dense_rank()

id	grade	rank
5	98	1
1	97	2
2	96	3
3	95	4
4	95	4
6	94	5

select id, grade, dense_rank() over(order by grade) as rank from data_table

row_number()

id	grade	rank
5	98	1
1	97	2
2	96	3
3	95	4
4	95	5
6	94	6

select id, grade, row_number() over(order by grade) as rank from data_table