DELETE FROM courses WHERE id_course = 'course128';
DELETE FROM courses WHERE id_course = 'course156';
DELETE FROM courses WHERE id_course = 'course57';
DELETE FROM courses WHERE id_course = 'course148';
DELETE FROM courses WHERE id_course = 'course93';
DELETE FROM courses WHERE id_course = 'course19';
DELETE FROM courses WHERE id_course = 'course116';
DELETE FROM courses WHERE id_course = 'course34';
DELETE FROM courses WHERE id_course = 'course9';
DELETE FROM courses WHERE id_course = 'course144';
DELETE FROM courses WHERE id_course = 'course27';
DELETE FROM courses WHERE id_course = 'course29';
