diff --git a/backend/app/routes.py b/backend/app/routes.py
index 8e3d367..17ff3c8 100644
--- a/backend/app/routes.py
+++ b/backend/app/routes.py
@@ -4759,7 +4759,7 @@ def list_package_artifacts(
         db.query(PackageVersion.artifact_id)
         .filter(PackageVersion.package_id == package.id)
     )
-    combined_artifact_ids = upload_artifact_ids.union(version_artifact_ids).subquery()
+    combined_artifact_ids = upload_artifact_ids.union(version_artifact_ids).subquery().select()
 
     query = db.query(Artifact).filter(Artifact.id.in_(combined_artifact_ids))