如何在 MySQL 表数据和列中执行转置操作？

Question

For instance, I have a table named 'stdinfo' like

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

now I want transform the table result like below

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

There is one important thing is that the number of rows is not fixed.

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/