And or Or operation supports the none condition

op_condition.go

@@ -133,6 +133,9 @@ func newCondGroup(sep string) OpBuilder {
 			panic(fmt.Errorf("sqlx: unsupported value type %T for op '%s:%v'", _op.Val, _op.Kind, _op.Op))
 		}
 
+		if len(ss) == 0 {
+			return ""
+		}
 		return fmt.Sprintf("(%s)", strings.Join(ss, sep))
 	})
 }

op_condition_test.go

@@ -46,4 +46,25 @@ func TestAnd(t *testing.T) {
 			}
 		}
 	}
+
+	if sql := BuildOper(NewArgsBuilder(MySQL), op.And()); sql != "" {
+		t.Errorf("expect an empty sql, but got: %s", sql)
+	}
+
+	expectsql = "SELECT `c1`, `c2` FROM `table` WHERE `id`=?"
+	expectargs = []interface{}{1}
+	sql, args = Selects("c1", "c2").From("table").Where(op.And(op.Eq("id", 1), op.And())).Build()
+	if expectsql != sql {
+		t.Errorf("expect sql: %s; but got: %s;", expectsql, sql)
+	}
+
+	if len(args) != len(expectargs) {
+		t.Errorf("expect %d args, but got %d", len(expectargs), len(args))
+	} else {
+		for i, arg := range args {
+			if expect := expectargs[i]; expect != arg {
+				t.Errorf("args %d: expect '%v', but got '%v'", i, expect, arg)
+			}
+		}
+	}
 }

utils.go

@@ -710,6 +710,10 @@ func isZero(v reflect.Value) bool {
 }
 
 func toslice[S1 ~[]E1, E1, E2 any](srcs S1, to func(E1) E2) (dsts []E2) {
+	if len(srcs) == 0 {
+		return
+	}
+
 	dsts = make([]E2, len(srcs))
 	for i, src := range srcs {
 		dsts[i] = to(src)