diff --git a/src/kit/taosdemo/taosdemo.c b/src/kit/taosdemo/taosdemo.c
index 8db149a55962ead9f10204d850298c98ac6cfad6..2536736cb6beba262f668a2a48ca940173f53f29 100644
--- a/src/kit/taosdemo/taosdemo.c
+++ b/src/kit/taosdemo/taosdemo.c
@@ -1010,6 +1010,7 @@ static void parse_args(int argc, char *argv[], SArguments *arguments) {
                     exit(EXIT_FAILURE);
                 }
                 arguments->datatype[0] = argv[i];
+                arguments->datatype[1] = NULL;
             } else {
                 // more than one col
                 int index = 0;