diff --git a/example/src/demoapi.c b/example/src/demoapi.c
index 45da88fa1b..afa9e19d4d 100644
--- a/example/src/demoapi.c
+++ b/example/src/demoapi.c
@@ -176,7 +176,7 @@ static int print_result(char *tbname, TAOS_RES* res, int block) {
     }
 
     if (block) {
-        warnPrint("%s", "call taos_fetch_block()\n");
+        warnPrint("%s", "call taos_fetch_block(), don't call taos_fetch_lengths()\n");
         int rows = 0;
         while ((rows = taos_fetch_block(res, &row))) {
             int *lengths = taos_fetch_lengths(res);
diff --git a/tests/pytest/insert/binary.py b/tests/pytest/insert/binary.py
index ffd1d6cb8c..28621f777b 100644
--- a/tests/pytest/insert/binary.py
+++ b/tests/pytest/insert/binary.py
@@ -35,8 +35,8 @@ class TDTestCase:
         tdSql.prepare()
 
         tdLog.info('=============== step1')
-        tdLog.info('create table tb (ts timestamp, speed binary(5))')
-        tdSql.execute('create table tb (ts timestamp, speed binary(5))')
+        tdLog.info('create table tb (ts timestamp, speed binary(10))')
+        tdSql.execute('create table tb (ts timestamp, speed binary(10))')
         tdLog.info("insert into tb values (now, ) -x step1")
         tdSql.error("insert into tb values (now, )")
         tdLog.info('=============== step2')
@@ -49,27 +49,29 @@ class TDTestCase:
         tdLog.info("tdSql.checkData(0, 0, '1234')")
         tdSql.checkData(0, 0, '1234')
         tdLog.info('=============== step3')
-        tdLog.info("insert into tb values (now+2a, '23456')")
-        tdSql.execute("insert into tb values (now+2a, '23456')")
+        tdLog.info("insert into tb values (now+2a, '0123456789')")
+        tdSql.execute("insert into tb values (now+2a, '0123456789')")
         tdLog.info('select speed from tb order by ts desc')
         tdSql.query('select speed from tb order by ts desc')
         tdLog.info('tdSql.checkRow(2)')
         tdSql.checkRows(2)
         tdLog.info('==> $data00')
-        tdLog.info("tdSql.checkData(0, 0, '23456')")
-        tdSql.checkData(0, 0, '23456')
+        tdLog.info("tdSql.checkData(0, 0, '0123456789')")
+        tdSql.checkData(0, 0, '0123456789')
         tdLog.info('=============== step4')
-        tdLog.info("insert into tb values (now+3a, '345678')")
-        tdSql.error("insert into tb values (now+3a, '345678')")
+        tdLog.info("insert into tb values (now+3a, '01234567890')")
+        tdSql.error("insert into tb values (now+3a, '01234567890')")
         tdLog.info("insert into tb values (now+3a, '34567')")
         tdSql.execute("insert into tb values (now+3a, '34567')")
+        tdLog.info("insert into tb values (now+4a, NULL)")
+        tdSql.execute("insert into tb values (now+4a, NULL)")
         tdLog.info('select speed from tb order by ts desc')
         tdSql.query('select speed from tb order by ts desc')
-        tdLog.info('tdSql.checkRow(3)')
-        tdSql.checkRows(3)
-        tdLog.info('==> $data00')
-        tdLog.info("tdSql.checkData(0, 0, '34567')")
-        tdSql.checkData(0, 0, '34567')
+        tdSql.checkRows(4)
+        tdLog.info("tdSql.checkData(0, 0, '0123456789')")
+        tdSql.checkData(0, 0, '0123456789')
+        tdLog.info("tdSql.checkData(3, 0, None)")
+        tdSql.checkData(3, 0, None)
         tdLog.info("insert into tb values (now+4a, \"'';\")")
 
         if platform.system() == "Linux":