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select concat(m.first_name, ' ' , m.last_name) manager_id,
concat(e.first_name, ' ' , e.last_name) employee_id
from employees e
left join employees m on m.employee_id = e.manager_id
order by manager_id;
Sie müssen das Schlüsselwort AS in zu ändern, nachdem der Auswahl concat (m.first_name, '', m.last_name). –