diff --git a/influxql/functions.go b/influxql/functions.go
index eff918534ee..ef9704c33e3 100644
--- a/influxql/functions.go
+++ b/influxql/functions.go
@@ -107,6 +107,10 @@ func InitializeReduceFunc(c *Call) (ReduceFunc, error) {
 	case "last":
 		return ReduceLast, nil
 	case "percentile":
+		if len(c.Args) != 2 {
+			return nil, fmt.Errorf("expected float argument in percentile()")
+		}
+
 		lit, ok := c.Args[1].(*NumberLiteral)
 		if !ok {
 			return nil, fmt.Errorf("expected float argument in percentile()")
diff --git a/influxql/functions_test.go b/influxql/functions_test.go
index 2dfaa11ffe9..1f965e256f4 100644
--- a/influxql/functions_test.go
+++ b/influxql/functions_test.go
@@ -65,3 +65,36 @@ func TestMapMean(t *testing.T) {
 
 	}
 }
+
+func TestInitializeReduceFuncPercentile(t *testing.T) {
+	// No args
+	c := &Call{
+		Name: "percentile",
+		Args: []Expr{},
+	}
+	_, err := InitializeReduceFunc(c)
+	if err == nil {
+		t.Errorf("InitializedReduceFunc(%v) expected error. got nil", c)
+	}
+
+	if exp := "expected float argument in percentile()"; err.Error() != exp {
+		t.Errorf("InitializedReduceFunc(%v) mismatch. exp %v got %v", c, exp, err.Error())
+	}
+
+	// No percentile arg
+	c = &Call{
+		Name: "percentile",
+		Args: []Expr{
+			&VarRef{Val: "field1"},
+		},
+	}
+
+	_, err = InitializeReduceFunc(c)
+	if err == nil {
+		t.Errorf("InitializedReduceFunc(%v) expected error. got nil", c)
+	}
+
+	if exp := "expected float argument in percentile()"; err.Error() != exp {
+		t.Errorf("InitializedReduceFunc(%v) mismatch. exp %v got %v", c, exp, err.Error())
+	}
+}