diff --git a/motion/operations/resolve.py b/motion/operations/resolve.py
index de14c6c7..9b24ebf4 100644
--- a/motion/operations/resolve.py
+++ b/motion/operations/resolve.py
@@ -187,16 +187,19 @@ def execute(self, input_data: List[Dict]) -> Tuple[List[Dict], float]:
 
         The method also calculates and logs statistics such as comparisons saved by blocking and self-join selectivity.
         """
+        if len(input_data) == 0:
+            return [], 0
+
         blocking_keys = self.config.get("blocking_keys", [])
         blocking_threshold = self.config.get("blocking_threshold")
         blocking_conditions = self.config.get("blocking_conditions", [])
         input_schema = self.config.get("input", {}).get("schema", {})
+        if not blocking_keys:
+            # Set them to all keys in the input data
+            blocking_keys = list(input_data[0].keys())
         limit_comparisons = self.config.get("limit_comparisons")
         total_cost = 0
 
-        if len(input_data) == 0:
-            return [], 0
-
         def is_match(item1: Dict[str, Any], item2: Dict[str, Any]) -> bool:
             return any(
                 eval(condition, {"input1": item1, "input2": item2})