update

mec-biz/src/main/java/com/ym/mec/biz/service/impl/MusicGroupServiceImpl.java

@@ -1005,13 +1005,18 @@ public class MusicGroupServiceImpl extends BaseServiceImpl<String, MusicGroup> i
 
 		musicGroupQuitDao.insert(musicGroupQuit);
 
-		classGroupStudentMapperDao.deleteStudentByMusicGroupId(musicGroupId, userId);
-
 		// 判断乐器是否是租赁
 		StudentRegistration studentRegistration = studentRegistrationDao.queryByUserIdAndMusicGroupId(userId, musicGroupId);
 		if (studentRegistration == null) {
 			throw new BizException("用户注册信息不存在");
 		}
+		//更新学员在班级的状态
+		classGroupStudentMapperDao.deleteStudentByMusicGroupId(musicGroupId, userId);
+		
+		//更新班级人数
+		List<Integer> classGroupIdList = classGroupStudentMapperDao.queryClassGroupIdList(musicGroupId, userId, GroupType.MUSIC);
+		classGroupDao.batchUpdateStudentNumMinusOne(classGroupIdList);
+		
 		// 删除未上课
 		courseScheduleService.batchDeleteMusicGroupCourseWithStudent(musicGroupId, userId, GroupType.MUSIC);