Ersetzen Sie LEFT JOIN durch JOIN
Select pro_id, surname, firstname, group_concat(degree,school,year) as qual,concat(Title,year) as work
from profile
join qualification on qualification.pro_id = profile.pro_id
join projects on projects.pro_id = profile.pro_id group by pro_id
Was ist der Unterschied zwischen "INNER JOIN" und " OUTER JOIN"?
