Question

I have three tables.

course
idcourse
name

mark
idmark
idstudent
idcourse
mark

student
idstudent
name

How to cross a query to such a result?

result
table Header

studentid   course1 course2 ... courseN

id1         mark1   mark2   ... markN

id2         mark1   mark2   ... markN

id3         mark1   mark2   ... markN

Answer 1

Best I can think if is to use the group_concat function.
Because a variable number of columns is just a maintenance nightmare.
You can strip the values from the coursegrades field apart by exploding the list in php or whatever comma separator you have in your client.

  /*First make a list of coursenames for the header.*/
  SELECT 'studentid' as idstudent
    , 'studentname' as studentname
    ,  GROUP_CONCAT(course.name ORDER BY couselist.idcourse) as coursegrades
  FROM course
  INNER JOIN (SELECT DISTINCT idcourse FROM mark) courselist
    ON (courselist.idcourse = course.idcourse)

UNION ALL 

  /*UNION ALL this with a list of grades per course*/
  SELECT idstudent
    , student.name as studentname
    , GROUP_CONCAT(IFNULL(mark.mark,'') ORDER BY courselist.idcourse) as coursegrades
  FROM course
  INNER JOIN (SELECT DISTINCT idcourse FROM mark) courselist
    ON (courselist.idcourse = course.idcourse)
  LEFT JOIN mark ON (mark.idcourse = courselist.idcourse)
  INNER JOIN student ON (student.idstudent = mark.idstudent)
  GROUP BY student