如何在MySql表数据和列中执行转置操作？

Question

例如，我有一个名为'stdinfo'的表，如

Id   Name    Mark
-----------------
1    Helal   10
2    Shakil  15
...  ...     ...
...  ...     ...
...  ...     ...

现在我想转换表格结果如下

Name  Helal Shakil ...
----------------------
Id    1     2      ...
Mark  10    15     ...

有一个重要的事情是行数不固定。

请任何人帮我写sql查询来获得这个结果。

先谢谢...

Answer 1

You can try this,
Table
--------------------------------------------------
subject_id    subjectname   classid  teacher_id
---------------------------------------------------
3           Math         3          T-1
4         Economics      4          T-1
5          Physcis       3          T-1
--------------------------------------------------

Query:

SELECT  sum( if( subjectname = 'Math', subject_id, 0 ) ) AS 'Economics',  
sum( if( subjectname = 'Economics', subject_id, 0 ) ) AS 'Math', 
sum( if( subjectname = 'Physcis', subject_id, 0 ) ) AS 'Physcis' 
FROM tbsubject group by subjectname

Output:
----------------------------
Math   Economics  Physcis
---------------------------
0   4       0
3   0       0
0   0       5
----------------------------

Or you can create a view by programming.more example see pivot table
http://www.krishnasunuwar.com.np/2011/02/crosstab-query-pivot-table-or-transformation-of-rows-into-columns/