Split and save the data selectively from one table to another mysql - php

Question

Split the data selectively
I have a table with following fields
Table-1
Publication_ID, Student_ID, Q1,A1,Q2,A2,Q3,A3,Q4,A4......................Q249,A249,Q250,A250
Sample data
100, 123, 1, B, 2, A, 3, C,4, B, 5, D, 6, B,..........................120, C
100, 124, 1, C, 2, C, 3, D,4, C, 5, D, 6, B,.....................109, B
100, 125, 1, B, 2, C, 3, C,4, B, 5, D, 6, A,..........................120, C
100, 126, 1, C, 2, B, 3, A,4, B, 5, C, 6, D,..............................................250, D
Now I would like to save the data od above table to Another table in this format
Table-2
Publication_ID, Student_ID, Q,A
100, 123, 1,B
100, 123, 2,A
100, 123, 3,C
100, 123, 4,B
100, 123, 5,D
100, 123, 6,B
100, 124, 2,A
100, 124, 3,C
100, 124, 4,B
100, 124, 5,D
100, 124, 6,B
100, 125, 1,B
100, 125, 2,A
100, 125, 3,C
100, 125, 4,B
100, 125, 5,D
100, 125, 6,B
Please note that the number of field filled in the table 1 may not be same for all the rows of data. So it should not insert empty fields to the Table-2 from Table-1
Please help me in this regard

Answer 1

INSERT INTO table-2(SELECT Publication_ID,Student_ID,Q1,Q2,....A1,A2... FROM table-1)
If i understood that correctly

Answer 2

I assume you are trying to normalize some kind of table. So it shouldn't be an issue to perform multiple data manipulation statements in order to achieve the desired result. Something like that might do the trick:
SET autocommit = 0
-- repeat for n for 1 to 249
INSERT INTO T2
SELECT Publication_ID, Student_ID, Qn, An WHERE Qn IS NOT NULL
COMMIT
If you really need to execute the migration without using a host language, you could use a procedure:
CREATE PROCEDURE migrate()
BEGIN
DELETE FROM T2;
SET #n = 1;
REPEAT
SET #p = CONCAT('INSERT INTO T2 SELECT Publication_ID, Student_ID, Q', #n, ' as Q A', #n, ' WHERE Q IS NOT NULL');
PREPARE stmt FROM #p;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
SET #n = #n+1;
UNTIL #n > 249
END REPEAT;
END //
CALL migrate()