@@ -635,7 +635,7 @@ public class ClassGroupServiceImpl extends BaseServiceImpl<Integer, ClassGroup>
musicGroupDao.update(musicGroup);
}
if(classGroupAndTeachers == null || classGroupAndTeachers.size()==0){
- return classGroupAndTeachers;
+ return null;
List<Integer> classGroupIds = classGroupAndTeachers.stream().map(ClassGroupTeachersDto::getId).collect(Collectors.toList());