MySQL cheatsheet: stored procedure

stored_procedure.sql

DELIMITER // -- we need to change it, in order to be able of writing ; in the instructions
CREATE PROCEDURE get_age(IN user_id INT, OUT user_age INT) -- the procedure has one parameter and returns one variable
BEGIN
    SELECT age INTO user_age FROM Students WHERE id = user_id;
    -- more instructions... --
END //
DELIMITER ; -- don't forget to restore the original delimiter !

CALL get_age(12, @age); -- call the procedure, send a parameter and store the result into the session variable age