update 退团，没有报名订单处理

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

@@ -2021,7 +2021,7 @@ public class MusicGroupServiceImpl extends BaseServiceImpl<String, MusicGroup> i
             musicGroupSubjectPlan.setUpdateTime(date);
             //减去缴费人数（器乐收费，0元时不减缴费人数）
             if (musicGroup.getCourseViewType().equals(CourseViewTypeEnum.CLOUD_TEACHER)) {
-                if (studentPaymentOrder.getPaymentAccountNo() != null && studentPaymentOrder.getPaymentAccountNo().equals("205")) {
+                if (studentPaymentOrder!= null && studentPaymentOrder.getPaymentAccountNo() != null && studentPaymentOrder.getPaymentAccountNo().equals("205")) {
                     musicGroupSubjectPlan.setPaidZeroNum(musicGroupSubjectPlan.getPaidZeroNum() - 1);
                     musicGroupSubjectPlan.setPaidStudentNum(musicGroupSubjectPlan.getPaidStudentNum() - 1);
                 }