diff --git a/operator.go b/operator.go
index 8c2f31f..eb38ac6 100644
--- a/operator.go
+++ b/operator.go
@@ -165,15 +165,28 @@ func cmpNodeSetString(t iterator, op string, m, n interface{}) bool {
 func cmpNodeSetNodeSet(t iterator, op string, m, n interface{}) bool {
 	a := m.(query)
 	b := n.(query)
-	x := a.Select(t)
-	if x == nil {
-		return false
-	}
-	y := b.Select(t)
-	if y == nil {
-		return false
+	for {
+		x := a.Select(t)
+		if x == nil {
+			return false
+		}
+
+		y := b.Select(t)
+		if y == nil {
+			return false
+		}
+
+		for {
+			if cmpStringStringF(op, x.Value(), y.Value()) {
+				return true
+			}
+			if y = b.Select(t); y == nil {
+				break
+			}
+		}
+		// reset
+		b.Evaluate(t)
 	}
-	return cmpStringStringF(op, x.Value(), y.Value())
 }
 
 func cmpStringNumeric(t iterator, op string, m, n interface{}) bool {