DELETE FROM courses WHERE id_course = 'course134';
DELETE FROM courses WHERE id_course = 'course16';
DELETE FROM courses WHERE id_course = 'course64';
DELETE FROM courses WHERE id_course = 'course101';
DELETE FROM courses WHERE id_course = 'course136';
DELETE FROM courses WHERE id_course = 'course51';
DELETE FROM courses WHERE id_course = 'course151';
DELETE FROM courses WHERE id_course = 'course34';
DELETE FROM courses WHERE id_course = 'course75';
DELETE FROM courses WHERE id_course = 'course121';
DELETE FROM courses WHERE id_course = 'course126';
DELETE FROM courses WHERE id_course = 'course77';
