diff --git a/src/query/src/promql/planner.rs b/src/query/src/promql/planner.rs
index 11a4b35767..c7de23974c 100644
--- a/src/query/src/promql/planner.rs
+++ b/src/query/src/promql/planner.rs
@@ -1560,23 +1560,30 @@ impl PromPlanner {
         let mut result = FunctionArgs::default();
 
         for arg in args {
-            match *arg.clone() {
-                PromExpr::Subquery(_)
-                | PromExpr::VectorSelector(_)
-                | PromExpr::MatrixSelector(_)
-                | PromExpr::Extension(_)
-                | PromExpr::Aggregate(_)
-                | PromExpr::Paren(_)
-                | PromExpr::Call(_) => {
-                    if result.input.replace(*arg.clone()).is_some() {
-                        MultipleVectorSnafu { expr: *arg.clone() }.fail()?;
+            // First try to parse as literal expression (including binary expressions like 100.0 + 3.0)
+            if let Some(expr) = Self::try_build_literal_expr(arg) {
+                result.literals.push(expr);
+            } else {
+                // If not a literal, treat as vector input
+                match arg.as_ref() {
+                    PromExpr::Subquery(_)
+                    | PromExpr::VectorSelector(_)
+                    | PromExpr::MatrixSelector(_)
+                    | PromExpr::Extension(_)
+                    | PromExpr::Aggregate(_)
+                    | PromExpr::Paren(_)
+                    | PromExpr::Call(_)
+                    | PromExpr::Binary(_)
+                    | PromExpr::Unary(_) => {
+                        if result.input.replace(*arg.clone()).is_some() {
+                            MultipleVectorSnafu { expr: *arg.clone() }.fail()?;
+                        }
                     }
-                }
 
-                _ => {
-                    let expr =
-                        Self::get_param_as_literal_expr(&Some(Box::new(*arg.clone())), None, None)?;
-                    result.literals.push(expr);
+                    _ => {
+                        let expr = Self::get_param_as_literal_expr(&Some(arg.clone()), None, None)?;
+                        result.literals.push(expr);
+                    }
                 }
             }
         }
diff --git a/tests/cases/standalone/common/promql/math.result b/tests/cases/standalone/common/promql/math.result
index 93d3b44064..bef7a5fea3 100644
--- a/tests/cases/standalone/common/promql/math.result
+++ b/tests/cases/standalone/common/promql/math.result
@@ -181,7 +181,15 @@ Error: 2000(InvalidSyntax), expected type vector in call to function 'deg', got
 -- SQLNESS SORT_RESULT 3 1
 TQL EVAL (0, 20, '5s') rad(180 * angles{unit="radians"});
 
-Error: 1004(InvalidArguments), Invalid function argument for unknown
++---------------------+-----------------------------+---------+
+| ts                  | radians(Float64(180) * val) | unit    |
++---------------------+-----------------------------+---------+
+| 1970-01-01T00:00:00 | 0.0                         | radians |
+| 1970-01-01T00:00:05 | 4.934813740258846           | radians |
+| 1970-01-01T00:00:10 | 9.869627480517693           | radians |
+| 1970-01-01T00:00:15 | 14.80444122077654           | radians |
+| 1970-01-01T00:00:20 | 19.739254961035385          | radians |
++---------------------+-----------------------------+---------+
 
 -- Test sgn() function (returns sign of values: -1, 0, or 1)
 -- SQLNESS SORT_RESULT 3 1
@@ -275,12 +283,43 @@ TQL EVAL (25, 35, '5s') scalar(sgn(angles{unit="positive"}));
 -- SQLNESS SORT_RESULT 3 1
 TQL EVAL (25, 35, '5s') sgn(angles - 42.5);
 
-Error: 1004(InvalidArguments), Invalid function argument for unknown
++---------------------+-----------------------------+-----------+
+| ts                  | signum(val - Float64(42.5)) | unit      |
++---------------------+-----------------------------+-----------+
+| 1970-01-01T00:00:25 | -1.0                        | negative  |
+| 1970-01-01T00:00:25 | -1.0                        | radians   |
+| 1970-01-01T00:00:25 | 0.0                         | positive  |
+| 1970-01-01T00:00:25 | 1.0                         | degrees   |
+| 1970-01-01T00:00:30 | -1.0                        | negative  |
+| 1970-01-01T00:00:30 | -1.0                        | radians   |
+| 1970-01-01T00:00:30 | -1.0                        | small_pos |
+| 1970-01-01T00:00:30 | -1.0                        | zero      |
+| 1970-01-01T00:00:30 | 0.0                         | positive  |
+| 1970-01-01T00:00:30 | 1.0                         | degrees   |
+| 1970-01-01T00:00:35 | -1.0                        | negative  |
+| 1970-01-01T00:00:35 | -1.0                        | radians   |
+| 1970-01-01T00:00:35 | -1.0                        | small_neg |
+| 1970-01-01T00:00:35 | -1.0                        | small_pos |
+| 1970-01-01T00:00:35 | -1.0                        | zero      |
+| 1970-01-01T00:00:35 | 0.0                         | positive  |
+| 1970-01-01T00:00:35 | 1.0                         | degrees   |
++---------------------+-----------------------------+-----------+
 
 -- SQLNESS SORT_RESULT 3 1
 TQL EVAL (0, 35, '5s') sgn(angles{unit="radians"} - pi());
 
-Error: 1004(InvalidArguments), Invalid function argument for unknown
++---------------------+----------------------------+
+| time                | signum(angles.val - .pi()) |
++---------------------+----------------------------+
+| 1970-01-01T00:00:00 | -1.0                       |
+| 1970-01-01T00:00:05 | -1.0                       |
+| 1970-01-01T00:00:10 | 1.0                        |
+| 1970-01-01T00:00:15 | 1.0                        |
+| 1970-01-01T00:00:20 | 1.0                        |
+| 1970-01-01T00:00:25 | 1.0                        |
+| 1970-01-01T00:00:30 | 1.0                        |
+| 1970-01-01T00:00:35 | 1.0                        |
++---------------------+----------------------------+
 
 -- SQLNESS SORT_RESULT 3 1
 TQL EVAL (25, 35, '5s') sgn(angles) * angles;
diff --git a/tests/cases/standalone/common/promql/timestamp_fn.result b/tests/cases/standalone/common/promql/timestamp_fn.result
index 2fee237dcd..a4b2b55e56 100644
--- a/tests/cases/standalone/common/promql/timestamp_fn.result
+++ b/tests/cases/standalone/common/promql/timestamp_fn.result
@@ -106,7 +106,19 @@ tql eval (0, 60, '30s') timestamp(timestamp_test) - time();
 -- Test timestamp() with other functions
 tql eval (0, 60, '30s') abs(timestamp(timestamp_test) - avg(timestamp(timestamp_test))) > 20;
 
-Error: 1004(InvalidArguments), Invalid function argument for unknown
+++
+++
+
+-- Test Issue 6707
+tql eval timestamp(demo_memory_usage_bytes * 1);
+
+++
+++
+
+tql eval timestamp(-demo_memory_usage_bytes);
+
+++
+++
 
 tql eval (0, 60, '30s') timestamp(timestamp_test) == 60;
 
diff --git a/tests/cases/standalone/common/promql/timestamp_fn.sql b/tests/cases/standalone/common/promql/timestamp_fn.sql
index a2f6e9e317..123bdeb588 100644
--- a/tests/cases/standalone/common/promql/timestamp_fn.sql
+++ b/tests/cases/standalone/common/promql/timestamp_fn.sql
@@ -36,6 +36,11 @@ tql eval (0, 60, '30s') timestamp(timestamp_test) - time();
 -- Test timestamp() with other functions
 tql eval (0, 60, '30s') abs(timestamp(timestamp_test) - avg(timestamp(timestamp_test))) > 20;
 
+-- Test Issue 6707
+tql eval timestamp(demo_memory_usage_bytes * 1);
+
+tql eval timestamp(-demo_memory_usage_bytes);
+
 tql eval (0, 60, '30s') timestamp(timestamp_test) == 60;
 
 -- Test timestamp() with multiple metrics