diff --git a/src/main/java/eu/hbp/mip/model/MiningQuery.java b/src/main/java/eu/hbp/mip/model/MiningQuery.java
index 139652a12796c4e7f3c2ad4735ca21724c62f5a6..41fde12d72a7e7299c889c2c76bc64b88eaf03ec 100644
--- a/src/main/java/eu/hbp/mip/model/MiningQuery.java
+++ b/src/main/java/eu/hbp/mip/model/MiningQuery.java
@@ -24,6 +24,7 @@ public class MiningQuery {
         this.variables = new LinkedList<>();
         this.covariables = new LinkedList<>();
         this.grouping = new LinkedList<>();
+        this.filters = "";
     }
 
     public List<Variable> getVariables() {