DELETE FROM courses WHERE id_course = 'course128';
DELETE FROM courses WHERE id_course = 'course158';
DELETE FROM courses WHERE id_course = 'course0';
DELETE FROM courses WHERE id_course = 'course28';
DELETE FROM courses WHERE id_course = 'course49';
DELETE FROM courses WHERE id_course = 'course166';
DELETE FROM courses WHERE id_course = 'course45';
DELETE FROM courses WHERE id_course = 'course149';
DELETE FROM courses WHERE id_course = 'course40';
