diff --git a/src/client/src/tscSql.c b/src/client/src/tscSql.c
index 261467ad29eb817a36c2a387a2b8acbd760564b1..ddff004f828f626a60c793893f4c552467d970ee 100644
--- a/src/client/src/tscSql.c
+++ b/src/client/src/tscSql.c
@@ -573,7 +573,7 @@ int taos_fetch_block(TAOS_RES *res, TAOS_ROW *rows) {
   *rows = pRes->urow;
 
   tscClearSqlOwner(pSql);
-  return pRes->numOfRows;
+  return (int32_t) pRes->numOfRows;
 }
 
 int taos_select_db(TAOS *taos, const char *db) {