该需求涉及到两个知识点:1、分析函数;2、行列转换。 先讲实现 第一步:建测试表 create table COL_TO_ROW ( COL1 VARCHAR2(20), COL2 VARCHAR2(20) ) insert into col_to_row values('A','1'); insert into col_to_row values('A','12'); insert into col_to_row values('B','2'); insert into col_to_row values('B','23'); insert into col_to_row values('C','3'); insert into col_to_row values('C','334'); insert into col_to_row values('C','355') select * from COL_TO_ROW 第二步:对表进行分组,组内编号1,2,3 select col1,col2,row_number()over(partition by col1 order by col2)colnum from COL_TO_ROW 第三步:行列转换,完成 select col1,max(decode(colnum,1,col2,null))colA,max(decode(colnum,2,col2,null))colB,max(decode(colnum,3,col2,null))colC from ( select col1,col2,row_number()over(partition by col1 order by col2)colnum from COL_TO_ROW )group by col1再讲知识点 1、row_number()over(partition by col1 order by col2)colnum 通过col1字段进行分组,并组内编号 row_number() over ([partition by col1] order by col2) ) as 别名 表示根据col1分组,在分组内部根据 col2排序 而这个“别名”的值就表示每组内部排序后的顺序编号(组内连续的唯一的),[partition by col1] 可省略。关于该知识点的实例详解,可以进我空间看看:http://user.qzone.qq.com/362701082/blog/1322635025 2、max(decode(colnum,1,col2,null))colA
先讲实现
第一步:建测试表
create table COL_TO_ROW
(
COL1 VARCHAR2(20),
COL2 VARCHAR2(20)
)
insert into col_to_row values('A','1');
insert into col_to_row values('A','12');
insert into col_to_row values('B','2');
insert into col_to_row values('B','23');
insert into col_to_row values('C','3');
insert into col_to_row values('C','334');
insert into col_to_row values('C','355')
select * from COL_TO_ROW
第二步:对表进行分组,组内编号1,2,3
select col1,col2,row_number()over(partition by col1 order by col2)colnum from COL_TO_ROW 第三步:行列转换,完成
select col1,max(decode(colnum,1,col2,null))colA,max(decode(colnum,2,col2,null))colB,max(decode(colnum,3,col2,null))colC from (
select col1,col2,row_number()over(partition by col1 order by col2)colnum from COL_TO_ROW
)group by col1再讲知识点
1、row_number()over(partition by col1 order by col2)colnum
通过col1字段进行分组,并组内编号
row_number() over ([partition by col1] order by col2) ) as 别名
表示根据col1分组,在分组内部根据 col2排序
而这个“别名”的值就表示每组内部排序后的顺序编号(组内连续的唯一的),[partition by col1] 可省略。关于该知识点的实例详解,可以进我空间看看:http://user.qzone.qq.com/362701082/blog/1322635025
2、max(decode(colnum,1,col2,null))colA