fix：运营指标搜索繁忙

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

@@ -714,7 +714,7 @@ public class StudentManageServiceImpl implements StudentManageService {
             for (Student4operating student4operating : dataList) {
                 List<UserGroupDto> userGroupDtos = userGroupsMap.get(student4operating.getStudentId());
                 if(!CollectionUtils.isEmpty(userGroupDtos)){
-                    student4operating.setGroupNames(userGroupDtos.stream().map(UserGroupDto::getGroupName).sorted().collect(Collectors.joining(",")));
+                    student4operating.setGroupNames(userGroupDtos.stream().filter(ug->StringUtils.isNotBlank(ug.getGroupName())).map(UserGroupDto::getGroupName).sorted().collect(Collectors.joining(",")));
                 }
             }
         }

mec-biz/src/main/resources/config/mybatis/StudentMapper.xml

@@ -635,7 +635,7 @@
             DISTINCT sub.*
         FROM
             student stu
-            LEFT JOIN `subject` sub ON FIND_IN_SET( stu.subject_id_list_, sub.id_ )
+            LEFT JOIN `subject` sub ON FIND_IN_SET( sub.id_, stu.subject_id_list_ )
         WHERE
             stu.user_id_ IN
             <foreach collection="studentIds" item="studentId" open="(" close=")" separator=",">