diff --git a/src/sparql/tree.ts b/src/sparql/tree.ts
index 5c12524a2e31e712370c1771c8749fab2fdf9240..0fe89a24cfe23c1b0f7b6d135bb0190fa8af2393 100644
--- a/src/sparql/tree.ts
+++ b/src/sparql/tree.ts
@@ -59,21 +59,24 @@ export const getTreeNodesFromParentNodeURI = async (parentNodeUri: string, auth?
 
   return await executeSparqlConstruct<OcTreeNode>(
     `
-        CONSTRUCT {
+      CONSTRUCT {
+        <${parentNodeUri}> ?p ?o.
+        ?node ?p2 ?o2.
+        ?node oct:graph ?g.
+      }
+      WHERE {
+        {
+          VALUES ?p { dcat:catalog dcat:dataset dcat:distribution dct:title dct:identifier rdf:type }
           <${parentNodeUri}> ?p ?o.
-          ?node ?p2 ?o2.
-          ?node oct:graph ?g.
-        }
-        WHERE {
-                VALUES ?p { dcat:catalog dcat:dataset dcat:distribution dct:title dct:identifier rdf:type }
-                VALUES ?p2 { dcat:catalog dcat:dataset dcat:distribution dct:title dct:identifier rdf:type }
-                <${parentNodeUri}> ?p ?o.
-                <${parentNodeUri}> (dcat:catalog|dcat:dataset|dcat:distribution){0,1} ?node.
-                ?node ?p2 ?o2
+        } UNION {
+          VALUES ?p2 { dcat:catalog dcat:dataset dcat:distribution dct:title dct:identifier rdf:type }
+          <${parentNodeUri}> (dcat:catalog|dcat:dataset|dcat:distribution){0,1} ?node.
+          ?node ?p2 ?o2 .
           GRAPH ?g {
-                ?node dct:identifier ?id
+            ?node dct:identifier ?id
           }
         }
+      }
     `,
     {
       context,