partial

test.sql

SELECT CONCAT(usr.name,' ', usr.lastname) AS usuario 
FROM users usr WHERE usr.user_id IN (SELECT usr.user_id from users usr 
    INNER JOIN user_types ON user_types.user_type_id = usr.user_id);
    

    SELECT 
    CONCAT(usr.name,' ', usr.lastname) AS nombre,
    courses.curseTitle, 
    cert.token_cert AS token
    FROM certifications cert
    INNER JOIN inscriptions ON inscriptions.inscription_id = cert.inscription_id
    INNER JOIN cursadas crs ON crs.cursada_id = inscriptions.cursada_id
    INNER JOIN courses ON courses.course_id = crs.cursada_id
    INNER JOIN users usr ON usr.user_id = inscriptions.user_id;