diff --git a/src/main/java/cz/muni/ics/kypo/training/adaptive/repository/ParticipantTaskAssignmentRepository.java b/src/main/java/cz/muni/ics/kypo/training/adaptive/repository/ParticipantTaskAssignmentRepository.java
index e6584c1e7666ead98914cb537599b4ad2469143b..656666109dbadfbfedc2483df76c691b9218f2f2 100644
--- a/src/main/java/cz/muni/ics/kypo/training/adaptive/repository/ParticipantTaskAssignmentRepository.java
+++ b/src/main/java/cz/muni/ics/kypo/training/adaptive/repository/ParticipantTaskAssignmentRepository.java
@@ -12,7 +12,7 @@ import java.util.List;
 @Repository
 public interface ParticipantTaskAssignmentRepository extends JpaRepository<ParticipantTaskAssignment, Long>, QuerydslPredicateExecutor<ParticipantTaskAssignment> {
 
-    @Query("SELECT p.task FROM ParticipantTaskAssignment p")
+    @Query("SELECT DISTINCT(p.task) FROM ParticipantTaskAssignment p")
     List<Task> findAllVisitedTasks();
 
     //TODO provide a SQL commands that returns all the relations between task transitions