diff --git a/source/libs/function/src/builtins.c b/source/libs/function/src/builtins.c
index 844bfb07fc..252d7db8e1 100644
--- a/source/libs/function/src/builtins.c
+++ b/source/libs/function/src/builtins.c
@@ -3221,7 +3221,7 @@ const SBuiltinFuncDefinition funcMgtBuiltins[] = {
   {
     .name = "now",
     .type = FUNCTION_TYPE_NOW,
-    .classification = FUNC_MGT_SCALAR_FUNC | FUNC_MGT_DATETIME_FUNC,
+    .classification = FUNC_MGT_SCALAR_FUNC | FUNC_MGT_DATETIME_FUNC | FUNC_MGT_KEEP_ORDER_FUNC,
     .translateFunc = translateNowToday,
     .getEnvFunc   = NULL,
     .initFunc     = NULL,
@@ -3231,7 +3231,7 @@ const SBuiltinFuncDefinition funcMgtBuiltins[] = {
   {
     .name = "today",
     .type = FUNCTION_TYPE_TODAY,
-    .classification = FUNC_MGT_SCALAR_FUNC | FUNC_MGT_DATETIME_FUNC,
+    .classification = FUNC_MGT_SCALAR_FUNC | FUNC_MGT_DATETIME_FUNC | FUNC_MGT_KEEP_ORDER_FUNC,
     .translateFunc = translateNowToday,
     .getEnvFunc   = NULL,
     .initFunc     = NULL,
diff --git a/tests/system-test/2-query/Now.py b/tests/system-test/2-query/Now.py
index db97cdad64..21ff1f4e06 100644
--- a/tests/system-test/2-query/Now.py
+++ b/tests/system-test/2-query/Now.py
@@ -101,6 +101,18 @@ class TDTestCase:
         self.now_check_ntb()
         self.now_check_stb()
 
+        ## TD-25540
+        tdSql.execute(f'create database db1')
+        tdSql.execute(f'use db1')
+        tdSql.execute(f"create table db1.tb (ts timestamp, c0 int)")
+        tdSql.execute(f'insert into db1.tb values(now + 1h, 1)')
+
+        for func in {"NOW", "NOW()", "TODAY()", "1", "'1970-01-01 00:00:00'"}:
+            tdSql.query(f"SELECT _wstart, count(*) FROM (SELECT ts, LAST(c0) FROM db1.tb WHERE ts > {func}) interval(1d);")
+            tdSql.checkRows(1)
+
+
+
     def stop(self):
         tdSql.close()
         tdLog.success(f"{__file__} successfully executed")