Oracle 10g:SQL将行合并为单行

我有一个返回以下数据结构的查询：

Course   Math   Science   Computer   Chemistry
------   ----   -------   --------   ---------
CI101     98
CI101     87
CI101             78
CI101             102
CI101                        23
CI101                        56
CI101                        89
CI101                                   45 

Course    Subject     Count
------    -------     -----
CI101     Math         98
....

如何使用SQL将其设置为以下结构：

Course   Math   Science   Computer   Chemistry
------   ----   -------   --------   ---------
CI101     98      78        23          45
CI101     87      102       56
CI101                       89

以下是我尝试过的SQL：

select course,
   case
     when subject = 'MATH' then
      count
   end as MATH,
   case
     when subject = 'SCIENCE' then
      count
   end as SCIENCE,
   case
     when subject = 'COMPUTER' then
      count
   end as COMPUTER,
   case
     when subject = 'CHEMISTRY' then
      count
   end as CHEMISTRY
 from t_course
 GROUP BY course, subject, count

表结构：

Course   Math   Science   Computer   Chemistry
------   ----   -------   --------   ---------
CI101     98
CI101     87
CI101             78
CI101             102
CI101                        23
CI101                        56
CI101                        89
CI101                                   45 

Course    Subject     Count
------    -------     -----
CI101     Math         98
....

谢谢。试试这个：

由于我没有Oracle，也没有看到这个问题的任何答案，所以我在sql server中完成了这项工作。这可以很容易地转换为Oracle sql

我认为，唯一需要转换的部分是ROW_NUMBER（）over（order by[count]）作为ROW_num，这基本上是为每个集合提供一个序列号

select CO.course,MA.count as  'MATH',SC.count as 'SCIENCE',CO.count as 'COMPUTER',CH.count as 'CHEMISTRY' from 
(select course,[count],ROW_NUMBER() over(order by  [count]) as row_num from t_course where subject = 'MATH')MA full outer join 
(select course,[count],ROW_NUMBER() over(order by  [count]) as row_num from t_course where subject = 'SCIENCE')SC on SC.row_num=MA.row_num full outer join 
(select course,[count],ROW_NUMBER() over(order by  [count]) as row_num from t_course where subject = 'COMPUTER')CO on CO.row_num=SC.row_num full outer join 
(select course,[count],ROW_NUMBER() over(order by  [count]) as row_num from t_course where subject = 'CHEMISTRY')CH on CO.row_num=CH.row_num  

请查看SQL fiddle演示

尝试以下操作：

由于我没有Oracle，也没有看到这个问题的任何答案，所以我在sql server中完成了这项工作。这可以很容易地转换为Oracle sql

我认为，唯一需要转换的部分是ROW_NUMBER（）over（order by[count]）作为ROW_num，这基本上是为每个集合提供一个序列号

select CO.course,MA.count as  'MATH',SC.count as 'SCIENCE',CO.count as 'COMPUTER',CH.count as 'CHEMISTRY' from 
(select course,[count],ROW_NUMBER() over(order by  [count]) as row_num from t_course where subject = 'MATH')MA full outer join 
(select course,[count],ROW_NUMBER() over(order by  [count]) as row_num from t_course where subject = 'SCIENCE')SC on SC.row_num=MA.row_num full outer join 
(select course,[count],ROW_NUMBER() over(order by  [count]) as row_num from t_course where subject = 'COMPUTER')CO on CO.row_num=SC.row_num full outer join 
(select course,[count],ROW_NUMBER() over(order by  [count]) as row_num from t_course where subject = 'CHEMISTRY')CH on CO.row_num=CH.row_num  

---

请参阅SQL fiddle演示

我在问题中添加了表结构在您想要的结果集中，一行与另一行的区别是什么？换句话说，为什么没有一个CI101行的总数是数学=185，科学=180，计算机=168，化学=45？我在问题中添加了表格结构，在你想要的结果集中，一行和另一行的区别是什么？换句话说，为什么没有一行CI101，数学=185，科学=180，计算机=168，化学=45？