Oracle排名函数(Rank)实例详解

--已知：两种排名方式(分区和不分区):使用和不使用partition

--两种计算方式(连续,不连续),对应函数：dense_rank,rank

·查询原始数据：学号,姓名,科目名,成绩

select

*

from

t_score

ottom" width="51">

S_ID

ottom" width="118">

S_NAME

ottom" width="120">

SUB_NAME

ottom" width="108">

score

ottom" width="51">

1

ottom" width="118">

张三

ottom" width="120">

语文

ottom" width="108">

80.00

ottom" width="51">

2

ottom" width="118">

李四

ottom" width="120">

数学

ottom" width="108">

80.00

ottom" width="51">

1

ottom" width="118">

张三

ottom" width="120">

数学

ottom" width="108">

0.00

ottom" width="51">

2

ottom" width="118">

李四

ottom" width="120">

语文

ottom" width="108">

50.00

ottom" width="51">

3

ottom" width="118">

张三丰

ottom" width="120">

语文

ottom" width="108">

10.00

ottom" width="51">

3

ottom" width="118">

张三丰

ottom" width="120">

数学

ottom" width="108">

　

ottom" width="51">

3

ottom" width="118">

张三丰

ottom" width="120">

体育

ottom" width="108">

120.00

ottom" width="51">

4

ottom" width="118">

杨过

ottom" width="120">

JAVA

ottom" width="108">

90.00

ottom" width="51">

5

ottom" width="118">

mike

ottom" width="120">

c++

ottom" width="108">

80.00

ottom" width="51">

3

ottom" width="118">

张三丰

ottom" width="120">

Oracle

ottom" width="108">

0.00

ottom" width="51">

4

ottom" width="118">

杨过

ottom" width="120">

Oracle

ottom" width="108">

77.00

ottom" width="51">

2

ottom" width="118">

李四

ottom" width="120">

Oracle

ottom" width="108">

77.00

·查询各学生科目为Oracle排名(简单排名)

select

sc.s_id,sc.s_name,sub_name,sc.score,

rank() over

(

order

by

score

desc

) 名次

from

t_score sc

where

sub_name='Oracle'

ottom" width="49">

S_ID

ottom" width="108">

S_NAME

ottom" width="108">

SUB_NAME

ottom" width="84">

score

ottom" width="60">

名次

ottom" width="49">

4

ottom" width="108">

杨过

ottom" width="108">

Oracle

ottom" width="84">

77.00

ottom" width="60">

1

ottom" width="49">

2

ottom" width="108">

李四

ottom" width="108">

Oracle

ottom" width="84">

77.00

ottom" width="60">

1

ottom" width="49">

3

ottom" width="108">

张三丰

ottom" width="108">

Oracle

ottom" width="84">

0.00

ottom" width="60">

3

对比：rank()与dense_rank()：非连续排名与连续排名(都是简单排名)

select

sc.s_id,

dense_rank() over

(

order

by

score

desc

) 名次

from

t_score sc

where

sub_name='Oracle'

ottom" width="49">

S_ID

ottom" width="96">

S_NAME

ottom" width="96">

SUB_NAME

ottom" width="84">

score

ottom" width="60">

名次

ottom" width="49">

4

ottom" width="96">

杨过

ottom" width="96">

Oracle

ottom" width="84">

77.00

ottom" width="60">

1

ottom" width="49">

2

ottom" width="96">

李四

ottom" width="96">

Oracle

ottom" width="84">

77.00

ottom" width="60">

1

ottom" width="49">

3

ottom" width="96">

张三丰

ottom" width="96">

Oracle

ottom" width="84">

0.00

ottom" width="60">

2

·查询各学生各科排名(分区排名)

select

sc.s_id,

rank() over

(

partition

by

sub_name

order

by

score

desc

) 名次

from

t_score sc

ottom" width="64">

S_ID

ottom" width="81">

S_NAME

ottom" width="96">

SUB_NAME

ottom" width="84">

score

ottom" width="72">

名次

ottom" width="64">

4

ottom" width="81">

杨过

ottom" width="96">

JAVA

ottom" width="84">

90.00

ottom" width="72">

1

ottom" width="64">

4

ottom" width="81">

杨过

ottom" width="96">

Oracle

ottom" width="84">

77.00

ottom" width="72">

1

ottom" width="64">

2

ottom" width="81">

李四

ottom" width="96">

Oracle

ottom" width="84">

77.00

ottom" width="72">

1

ottom" width="64">

3

ottom" width="81">

张三丰

ottom" width="96">

Oracle

ottom" width="84">

0.00

ottom" width="72">

3

ottom" width="64">

5

ottom" width="81">

mike

ottom" width="96">

c++

ottom" width="84">

80.00

ottom" width="72">

1

ottom" width="64">

3

ottom" width="81">

张三丰

ottom" width="96">

数学

ottom" width="84">

　

ottom" width="72">

1

ottom" width="64">

2

ottom" width="81">

李四

ottom" width="96">

数学

ottom" width="84">

80.00

ottom" width="72">

2

ottom" width="64">

1

ottom" width="81">

张三

ottom" width="96">

数学

ottom" width="84">

0.00

ottom" width="72">

3

ottom" width="64">

3

ottom" width="81">

张三丰

ottom" width="96">

体育

ottom" width="84">

120.00

ottom" width="72">

1

ottom" width="64">

1

ottom" width="81">

张三

ottom" width="96">

语文

ottom" width="84">

80.00

ottom" width="72">

1

ottom" width="64">

2

ottom" width="81">

李四

ottom" width="96">

语文

ottom" width="84">

50.00

ottom" width="72">

2

ottom" width="64">

3

ottom" width="81">

张三丰

ottom" width="96">

语文

ottom" width="84">

10.00

ottom" width="72">

3

·查询各科前2名(分区排名)

·类似：新闻表,求栏目点击率在前3位的新闻。
商品表,求各类别销售额在前10位的商品。

rush:sql;"> select * from ( select sc.s_id,dense_rank() over (partition by sub_name order by score desc) 名次 from t_score sc ) x where x.名次<=2

ottom" width="67">

S_ID

ottom" width="99">

S_NAME

ottom" width="111">

SUB_NAME

ottom" width="77">

score

ottom" width="64">

名次

ottom" width="67">

ottom" width="99">

ottom" width="111">

ottom" width="77">

ottom" width="64">

ottom" width="67">

ottom" width="99">

ottom" width="111">

ottom" width="77">

ottom" width="64">

ottom" width="67">

ottom" width="99">

ottom" width="111">

ottom" width="77">

ottom" width="64">

ottom" width="67">

ottom" width="99">

ottom" width="111">

ottom" width="77">

ottom" width="64">

ottom" width="67">

ottom" width="99">

ottom" width="111">

ottom" width="77">

ottom" width="64">

ottom" width="67">

ottom" width="99">

ottom" width="111">

ottom" width="77">

ottom" width="64">

ottom" width="67">

ottom" width="99">

ottom" width="111">

ottom" width="77">

ottom" width="64">

ottom" width="67">

ottom" width="99">

ottom" width="111">

ottom" width="77">

ottom" width="64">

ottom" width="67">

ottom" width="99">

ottom" width="111">

ottom" width="77">

ottom" width="64">

ottom" width="67">

ottom" width="99">

ottom" width="111">

ottom" width="77">

ottom" width="64">

·查询各同学总分

select

s_id,s_name,

sum

(score) sum_score

from

t_score

group

by

s_id,s_name

ottom" width="67">

S_ID

ottom" width="99">

S_NAME

ottom" width="111">

SUM_score

ottom" width="67">

1

ottom" width="99">

张三

ottom" width="111">

80.00

ottom" width="67">

2

ottom" width="99">

李四

ottom" width="111">

207.00

ottom" width="67">

3

ottom" width="99">

张三丰

ottom" width="111">

130.00

ottom" width="67">

4

ottom" width="99">

杨过

ottom" width="111">

167.00

ottom" width="67">

5

ottom" width="99">

mike

ottom" width="111">

80.00

·根据总分查询各同学名次

select

x.*,

rank() over (

order

by

sum_score

desc

) 名次

from

(

select

s_id,s_name ) x

ottom" width="67">

S_ID

ottom" width="99">

S_NAME

ottom" width="111">

SUM_score

ottom" width="77">

名次

ottom" width="67">

2

ottom" width="99">

李四

ottom" width="111">

207.00

ottom" width="77">

1

ottom" width="67">

4

ottom" width="99">

杨过

ottom" width="111">

167.00

ottom" width="77">

2

ottom" width="67">

3

ottom" width="99">

张三丰

ottom" width="111">

130.00

ottom" width="77">

3

ottom" width="67">

1

ottom" width="99">

张三

ottom" width="111">

80.00

ottom" width="77">

4

ottom" width="67">

5

ottom" width="99">

mike

ottom" width="111">

80.00

ottom" width="77">

4

语法：

rank() over (

order

by

排序字段 顺序)

rank() over (

partition

by

分组字段

order

by

排序字段 顺序)

1.顺序：asc|

desc

名次与业务相关：

示例：找求优秀学员：成绩：降序 迟到次数：升序

2.分区字段：根据什么字段进行分区。

问题：分区与分组有什么区别?

·分区只是将原始数据进行名次排列(记录数不变),

·分组是对原始数据进行聚合统计(记录数变少,每组返回一条),注意：聚合。

脚本：

rush:sql;"> create table t_score ( autoid number primary key,s_id number(3),s_name char(8) not null,sub_name varchar2(20),score number(10,2) ); insert into t_score (autoid,s_id,score) values (8,1,'张三 ','语文',80); insert into t_score (autoid,score) values (9,2,'李四 ','数学',score) values (10,0); insert into t_score (autoid,score) values (11,50); insert into t_score (autoid,score) values (12,3,'张三丰 ',10); insert into t_score (autoid,score) values (13,null); insert into t_score (autoid,score) values (14,'体育',120); insert into t_score (autoid,score) values (15,4,'杨过 ','java',90); insert into t_score (autoid,score) values (16,5,'mike ','c++',score) values (3,'oracle',score) values (4,77); insert into t_score (autoid,score) values (17,77); commit;

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