Datatables combine data from different columns into single row - sql

Question

Refer to the below image, how to merge all chapter into one single rows of different page number?
e.g.
Page 1 has 3 rows as there are 3 data at columns of chp 8,9,10
Page 2 has 5 rows as there are 5 data at columns of chp 8,9,1,11,12
So
how to have a single row of each page number and the all data placed at their own chp?
Basic SQL as below:
SELECT `mc_ee_page_id` as Page,
IF ( mc_ee_chp_id = 1, ( CASE
WHEN (is_marked = 0 and mk_no_mark = 1 ) THEN "Y"
WHEN (is_marked = 1 and mk_no_mark = -1) THEN "N"
WHEN (is_marked = 1 and mk_no_mark = 1 ) THEN "O" ELSE "X"
END ) , "" ) AS chp_1 ,
IF ( mc_ee_chp_id = 2, ( CASE
WHEN (is_marked = 0 and mk_no_mark = 1 ) THEN "Y"
WHEN (is_marked = 1 and mk_no_mark = -1) THEN "N"
WHEN (is_marked = 1 and mk_no_mark = 1 ) THEN "O" ELSE "X"
END ) , "" ) AS chp_2 ,
IF ( mc_ee_chp_id = 3, ( CASE
WHEN (is_marked = 0 and mk_no_mark = 1 ) THEN "Y"
WHEN (is_marked = 1 and mk_no_mark = -1) THEN "N"
WHEN (is_marked = 1 and mk_no_mark = 1 ) THEN "O" ELSE "X"
END ) , "" ) AS chp_3 ,
:
:
IF ( mc_ee_chp_id = 12, ( CASE
WHEN (is_marked = 0 and mk_no_mark = 1 ) THEN "Y"
WHEN (is_marked = 1 and mk_no_mark = -1) THEN "N"
WHEN (is_marked = 1 and mk_no_mark = 1 ) THEN "O" ELSE "X"
END ) , "" ) AS chp_12
FROM `maxcare_mc_ee_hw`
WHERE `stud_id` = '3312' AND `mc_ee_level_id` = '1'
GROUP BY mc_ee_chp_id, mc_ee_page_id
ORDER BY mc_ee_page_id asc
LIMIT 500

Answer 1

One way would be to GROUP the results of your SQL by making it the subquery of an outer query...
SELECT Page, MAX(chp_1) AS chp_1, MAX(chp_2) AS chp_2, MAX(chp_3) AS chp_3, MAX(chp_4) AS chp_4, MAX(chp_5) AS chp_5, MAX(chp_6) AS chp_6, MAX(chp_7) AS chp_7, MAX(chp_8) AS chp_8, MAX(chp_9) AS chp_9, MAX(chp_10) AS chp_10, MAX(chp_11) AS chp_11, MAX(chp_12) AS chp_12
FROM
(
-- *** paste your SQL in here ***
) AS indivdual_rows
GROUP BY Page
It assumes a page cannot have more than one non-blank value for the same chapter. If that is not the case, then it will only show the MAX alphabetical value.
Click here to go to SQL Fiddle to see it in action.