Include null results in group_concat

Question

I have two tables like this

profile_answers

+---------+------------+
|      id | class_name |
+---------+------------+
|       1 | Class         


        

Answer 1

SELECT id,IFNULL(samples,'NULL') sample FROM 
(
    SELECT
        AA.id,
        GROUP_CONCAT(DISTINCT BB.sample) samples
    FROM
        profile_answers AA LEFT JOIN educations BB
        ON AA.id = BB.profile_answers_id
    GROUP BY AA.id
) A;

Answer 2

Looks like you're missing your GROUP BY:

select profile_answers.id, GROUP_CONCAT(educations.sample) 
from profile_answers
LEFT JOIN educations ON educations.profile_answers_id = profile_answers.id
GROUP BY profile_answers.id

I also altered your JOIN to make the profile_answers table your main table.

Good luck.