oracle中行转列操作

Posted 2021-02-04 道法自然

数据准备阶段：

CREATE TABLE CC  (Student NVARCHAR2(2),Course NVARCHAR2(2),Score INT); 

INSERT into CC   
select N\'张三\',N\'语文\',78 from dual union all  
select N\'张三\',N\'数学\',87 from dual union all  
select N\'张三\',N\'英语\',82 from dual union all  
select N\'张三\',N\'物理\',90 from dual union all  
select N\'李四\',N\'语文\',65 from dual union all  
select N\'李四\',N\'数学\',77 from dual union all  
select N\'李四\',N\'英语\',65 from dual union all  
select N\'李四\',N\'物理\',85 from dual ;  
commit; 

操作如下：

方法一、

select 
student,
sum(decode(course,\'语文\',score)) 语文,
sum(decode(course,\'数学\',score)) 数学,
sum(decode(course,\'英语\',score)) 英语,
sum(decode(course,\'物理\',score)) 物理,
sum(score)
from cc group by student；

 

 方法二、

SELECT KIN.*,  
  KIN.a+KIN.b+KIN.c+KIN.d AS TOTAL  
FROM  
  (SELECT   *  
  FROM CC PIVOT ( MAX(SCORE) FOR COURSE IN (\'语文\' AS A , \'数学\' AS B, \'英语\' AS C,\'物理\' AS D) )  
  ) KIN; 

 

方法三、

select 
student，
sum(case when course = \'语文\' then score else 0 end )语文,
sum(case when course = \'数学\' then score else 0 end )数学,
sum(case when course = \'英语\' then score else 0 end )英语,
sum(case when course = \'物理\' then score else 0 end )物理
from cc group by student;

完。