--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
1·查询原始数据：学号,姓名,科目名,成绩
select * from t_score
| S_ID |
S_NAME |
SUB_NAME |
SCORE |
| 1 |
张三 |
语文 |
80.00 |
| 2 |
李四 |
数学 |
80.00 |
| 1 |
张三 |
数学 |
0.00 |
| 2 |
李四 |
语文 |
50.00 |
| 3 |
张三丰 |
语文 |
10.00 |
| 3 |
张三丰 |
数学 |
|
| 3 |
张三丰 |
体育 |
120.00 |
| 4 |
杨过 |
JAVA |
90.00 |
| 5 |
mike |
c++ |
80.00 |
| 3 |
张三丰 |
Oracle |
0.00 |
| 4 |
杨过 |
Oracle |
77.00 |
| 2 |
李四 |
Oracle |
77.00 |
2·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'
| S_ID |
S_NAME |
SUB_NAME |
SCORE |
名次 |
| 4 |
杨过 |
Oracle |
77.00 |
1 |
| 2 |
李四 |
Oracle |
77.00 |
1 |
| 3 |
张三丰 |
Oracle |
0.00 |
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,sc.s_name,sub_name,sc.score,
dense_rank() over (order by score desc) 名次
from t_score sc
where sub_name='Oracle'
| S_ID |
S_NAME |
SUB_NAME |
SCORE |
名次 |
| 4 |
杨过 |
Oracle |
77.00 |
1 |
| 2 |
李四 |
Oracle |
77.00 |
1 |
| 3 |
张三丰 |
Oracle |
0.00 |
2 |
3·查询各学生各科排名(分区排名)
select sc.s_id,sc.s_name,sub_name,sc.score,
rank() over
(partition by sub_name order by score desc) 名次
from t_score sc
| S_ID |
S_NAME |
SUB_NAME |
SCORE |
名次 |
| 4 |
杨过 |
JAVA |
90.00 |
1 |
| 4 |
杨过 |
Oracle |
77.00 |
1 |
| 2 |
李四 |
Oracle |
77.00 |
1 |
| 3 |
张三丰 |
Oracle |
0.00 |
3 |
| 5 |
mike |
c++ |
80.00 |
1 |
| 3 |
张三丰 |
数学 |
|
1 |
| 2 |
李四 |
数学 |
80.00 |
2 |
| 1 |
张三 |
数学 |
0.00 |
3 |
| 3 |
张三丰 |
体育 |
120.00 |
1 |
| 1 |
张三 |
语文 |
80.00 |
1 |
| 2 |
李四 |
语文 |
50.00 |
2 |
| 3 |
张三丰 |
语文 |
10.00 |
3 |
4·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。
select * from (
select sc.s_id,sc.s_name,sub_name,sc.score,
dense_rank() over
(partition by sub_name order by score desc) 名次
from t_score sc
) x
where x.名次<=2
| S_ID |
S_NAME |
SUB_NAME |
SCORE |
名次 |
| 4 |
杨过 |
JAVA |
90.00 |
1 |
| 4 |
杨过 |
Oracle |
77.00 |
1 |
| 2 |
李四 |
Oracle |
77.00 |
1 |
| 3 |
张三丰 |
Oracle |
0.00 |
2 |
| 5 |
mike |
c++ |
80.00 |
1 |
| 3 |
张三丰 |
数学 |
|
1 |
| 2 |
李四 |
数学 |
80.00 |
2 |
| 3 |
张三丰 |
体育 |
120.00 |
1 |
| 1 |
张三 |
语文 |
80.00 |
1 |
| 2 |
李四 |
语文 |
50.00 |
2 |
5·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
| S_ID |
S_NAME |
SUM_SCORE |
| 1 |
张三 |
80.00 |
| 2 |
李四 |
207.00 |
| 3 |
张三丰 |
130.00 |
| 4 |
杨过 |
167.00 |
| 5 |
mike |
80.00 |
6·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,sum(score) sum_score from t_score
group by s_id,s_name ) x
| S_ID |
S_NAME |
SUM_SCORE |
名次 |
| 2 |
李四 |
207.00 |
1 |
| 4 |
杨过 |
167.00 |
2 |
| 3 |
张三丰 |
130.00 |
3 |
| 1 |
张三 |
80.00 |
4 |
| 5 |
mike |
80.00 |
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： |
| 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, s_name, sub_name, score) values (8, 1, '张三 ', '语文', 80); insert into t_score (autoid, s_id, s_name, sub_name, score) values (9, 2, '李四 ', '数学', 80); insert into t_score (autoid, s_id, s_name, sub_name, score) values (10, 1, '张三 ', '数学', 0); insert into t_score (autoid, s_id, s_name, sub_name, score) values (11, 2, '李四 ', '语文', 50); insert into t_score (autoid, s_id, s_name, sub_name, score) values (12, 3, '张三丰 ', '语文', 10); insert into t_score (autoid, s_id, s_name, sub_name, score) values (13, 3, '张三丰 ', '数学', null); insert into t_score (autoid, s_id, s_name, sub_name, score) values (14, 3, '张三丰 ', '体育', 120); insert into t_score (autoid, s_id, s_name, sub_name, score) values (15, 4, '杨过 ', 'java', 90); insert into t_score (autoid, s_id, s_name, sub_name, score) values (16, 5, 'mike ', 'c++', 80); insert into t_score (autoid, s_id, s_name, sub_name, score) values (3, 3, '张三丰 ', 'oracle', 0); insert into t_score (autoid, s_id, s_name, sub_name, score) values (4, 4, '杨过 ', 'oracle', 77); insert into t_score (autoid, s_id, s_name, sub_name, score) values (17, 2, '李四 ', 'oracle', 77); commit; |
--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
1·查询原始数据：学号,姓名,科目名,成绩
select * from t_score
| S_ID |
S_NAME |
SUB_NAME |
SCORE |
| 1 |
张三 |
语文 |
80.00 |
| 2 |
李四 |
数学 |
80.00 |
| 1 |
张三 |
数学 |
0.00 |
| 2 |
李四 |
语文 |
50.00 |
| 3 |
张三丰 |
语文 |
10.00 |
| 3 |
张三丰 |
数学 |
|
| 3 |
张三丰 |
体育 |
120.00 |
| 4 |
杨过 |
JAVA |
90.00 |
| 5 |
mike |
c++ |
80.00 |
| 3 |
张三丰 |
Oracle |
0.00 |
| 4 |
杨过 |
Oracle |
77.00 |
| 2 |
李四 |
Oracle |
77.00 |
2·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'
| S_ID |
S_NAME |
SUB_NAME |
SCORE |
名次 |
| 4 |
杨过 |
Oracle |
77.00 |
1 |
| 2 |
李四 |
Oracle |
77.00 |
1 |
| 3 |
张三丰 |
Oracle |
0.00 |
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,sc.s_name,sub_name,sc.score,
dense_rank() over (order by score desc) 名次
from t_score sc
where sub_name='Oracle'
| S_ID |
S_NAME |
SUB_NAME |
SCORE |
名次 |
| 4 |
杨过 |
Oracle |
77.00 |
1 |
| 2 |
李四 |
Oracle |
77.00 |
1 |
| 3 |
张三丰 |
Oracle |
0.00 |
2 |
3·查询各学生各科排名(分区排名)
select sc.s_id,sc.s_name,sub_name,sc.score,
rank() over
(partition by sub_name order by score desc) 名次
from t_score sc
| S_ID |
S_NAME |
SUB_NAME |
SCORE |
名次 |
| 4 |
杨过 |
JAVA |
90.00 |
1 |
| 4 |
杨过 |
Oracle |
77.00 |
1 |
| 2 |
李四 |
Oracle |
77.00 |
1 |
| 3 |
张三丰 |
Oracle |
0.00 |
3 |
| 5 |
mike |
c++ |
80.00 |
1 |
| 3 |
张三丰 |
数学 |
|
1 |
| 2 |
李四 |
数学 |
80.00 |
2 |
| 1 |
张三 |
数学 |
0.00 |
3 |
| 3 |
张三丰 |
体育 |
120.00 |
1 |
| 1 |
张三 |
语文 |
80.00 |
1 |
| 2 |
李四 |
语文 |
50.00 |
2 |
| 3 |
张三丰 |
语文 |
10.00 |
3 |
4·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。
select * from (
select sc.s_id,sc.s_name,sub_name,sc.score,
dense_rank() over
(partition by sub_name order by score desc) 名次
from t_score sc
) x
where x.名次<=2
| S_ID |
S_NAME |
SUB_NAME |
SCORE |
名次 |
| 4 |
杨过 |
JAVA |
90.00 |
1 |
| 4 |
杨过 |
Oracle |
77.00 |
1 |
| 2 |
李四 |
Oracle |
77.00 |
1 |
| 3 |
张三丰 |
Oracle |
0.00 |
2 |
| 5 |
mike |
c++ |
80.00 |
1 |
| 3 |
张三丰 |
数学 |
|
1 |
| 2 |
李四 |
数学 |
80.00 |
2 |
| 3 |
张三丰 |
体育 |
120.00 |
1 |
| 1 |
张三 |
语文 |
80.00 |
1 |
| 2 |
李四 |
语文 |
50.00 |
2 |
5·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
| S_ID |
S_NAME |
SUM_SCORE |
| 1 |
张三 |
80.00 |
| 2 |
李四 |
207.00 |
| 3 |
张三丰 |
130.00 |
| 4 |
杨过 |
167.00 |
| 5 |
mike |
80.00 |
6·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,sum(score) sum_score from t_score
group by s_id,s_name ) x
| S_ID |
S_NAME |
SUM_SCORE |
名次 |
| 2 |
李四 |
207.00 |
1 |
| 4 |
杨过 |
167.00 |
2 |
| 3 |
张三丰 |
130.00 |
3 |
| 1 |
张三 |
80.00 |
4 |
| 5 |
mike |
80.00 |
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： |
| 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, s_name, sub_name, score) values (8, 1, '张三 ', '语文', 80); insert into t_score (autoid, s_id, s_name, sub_name, score) values (9, 2, '李四 ', '数学', 80); insert into t_score (autoid, s_id, s_name, sub_name, score) values (10, 1, '张三 ', '数学', 0); insert into t_score (autoid, s_id, s_name, sub_name, score) values (11, 2, '李四 ', '语文', 50); insert into t_score (autoid, s_id, s_name, sub_name, score) values (12, 3, '张三丰 ', '语文', 10); insert into t_score (autoid, s_id, s_name, sub_name, score) values (13, 3, '张三丰 ', '数学', null); insert into t_score (autoid, s_id, s_name, sub_name, score) values (14, 3, '张三丰 ', '体育', 120); insert into t_score (autoid, s_id, s_name, sub_name, score) values (15, 4, '杨过 ', 'java', 90); insert into t_score (autoid, s_id, s_name, sub_name, score) values (16, 5, 'mike ', 'c++', 80); insert into t_score (autoid, s_id, s_name, sub_name, score) values (3, 3, '张三丰 ', 'oracle', 0); insert into t_score (autoid, s_id, s_name, sub_name, score) values (4, 4, '杨过 ', 'oracle', 77); insert into t_score (autoid, s_id, s_name, sub_name, score) values (17, 2, '李四 ', 'oracle', 77); commit; |