fix bug

teachcloud-mark/src/main/resources/mapper/MarkTaskMapper.xml

@@ -483,7 +483,7 @@
     </select>
 
     <select id="exportAiMark" resultType="com.qmth.teachcloud.mark.dto.mark.manage.MarkAiExport">
-        select
+        select distinct
             bc.name as courseName,
             bc.code as courseCode,
             maqp.paper_number as paperNumber,