DELETE FROM courses WHERE id_course = 'course123';
DELETE FROM courses WHERE id_course = 'course32';
DELETE FROM courses WHERE id_course = 'course50';
DELETE FROM courses WHERE id_course = 'course13';
DELETE FROM courses WHERE id_course = 'course164';
DELETE FROM courses WHERE id_course = 'course41';
DELETE FROM courses WHERE id_course = 'course51';
DELETE FROM courses WHERE id_course = 'course174';
DELETE FROM courses WHERE id_course = 'course4';
DELETE FROM courses WHERE id_course = 'course62';
DELETE FROM courses WHERE id_course = 'course126';
DELETE FROM courses WHERE id_course = 'course160';
DELETE FROM courses WHERE id_course = 'course91';
