fix:test case error in sml.py

source/libs/parser/src/parInsert.c

@@ -2505,6 +2505,11 @@ int32_t smlBindData(void* handle, SArray* tags, SArray* colsSchema, SArray* cols
       }
     }
 
+    // set the null value for the columns that do not assign values
+    if ((spd->numOfBound < spd->numOfCols) && TD_IS_TP_ROW(row)) {
+      pBuilder->hasNone = true;
+    }
+
     tdSRowEnd(pBuilder);
     pDataBlock->size += extendedRowSize;
   }

tests/system-test/2-query/sml.py

@@ -53,7 +53,7 @@ class TDTestCase:
         tdSql.query(f"select * from {dbname}.t_0799064f5487946e5d22164a822acfc8 order by _ts")
         tdSql.checkRows(2)
         tdSql.checkData(0, 3, "kk")
-        tdSql.checkData(1, 3, None)
+        tdSql.checkData(1, 3, "")
 
 
         tdSql.query(f"select distinct tbname from {dbname}.`sys.if.bytes.out`")