这篇文章主要介绍了Oracle排名函数(Rank)实例详解,需要的朋友可以参考下
--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
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 |
·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 |
·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 |
·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 |
·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 |
·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;
ending...
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