How to limit multiple numbers by filtering multiple columns on MySql?

Question

I would like to get 50 questions from 4 different categories from the database. I want a different number of questions from each of the 4 different categories; my result set mus

Answer 1

You can use a UNION query to get all your questions at once:

(SELECT * FROM question WHERE categori_id=1 ORDER BY RAND() LIMIT 12)
UNION
(SELECT * FROM question WHERE categori_id=2 ORDER BY RAND() LIMIT 20)
UNION
(SELECT * FROM question WHERE categori_id=3 ORDER BY RAND() LIMIT 10)
UNION
(SELECT * FROM question WHERE categori_id=4 ORDER BY RAND() LIMIT 8)