diff --git a/bundles/io.github.linkedfactory.core/src/main/java/io/github/linkedfactory/core/rdf4j/kvin/KvinEvaluationStrategy.java b/bundles/io.github.linkedfactory.core/src/main/java/io/github/linkedfactory/core/rdf4j/kvin/KvinEvaluationStrategy.java
index 28e083f9..6c7ca2b0 100644
--- a/bundles/io.github.linkedfactory.core/src/main/java/io/github/linkedfactory/core/rdf4j/kvin/KvinEvaluationStrategy.java
+++ b/bundles/io.github.linkedfactory.core/src/main/java/io/github/linkedfactory/core/rdf4j/kvin/KvinEvaluationStrategy.java
@@ -327,7 +327,9 @@ boolean useHashJoin(TupleExpr leftArg, TupleExpr rightArg) {
             }
             if (rightFetch != null) {
                 // do not use hash join if required bindings are provided by left join argument
-                Set<String> leftAssured = leftArg.getAssuredBindingNames();
+                // in case of projections with aggregates we just use the projected binding names
+                Set<String> leftAssured = leftArg instanceof Projection ? leftArg.getBindingNames() :
+                        leftArg.getAssuredBindingNames();
                 return ! rightFetch.getRequiredBindings().stream().anyMatch(required -> leftAssured.contains(required));
             }
         }