课表同步调整修复bug

src/main/java/com/xjrsoft/module/schedule/util/DataUtil.java

@@ -487,7 +487,7 @@ public class DataUtil {
                     + "'" + teacherJson.get("name").getAsString() + "',"
                     + "'" + teacherJson.get("teacherSerialNo").getAsString() + "',";
             }else{
-                sql += "0,null,null,";
+                sql += "0,'',null,";
             }
             sql += coureseMap.get(asJsonObject.get("courseClassId").getAsString()) + ","
                 + "'" + asJsonObject.get("courseClassName").getAsString() + "',"