diff --git a/guix-data-service/model/guix-revision-package-derivation.scm b/guix-data-service/model/guix-revision-package-derivation.scm
index cb73114..2b0ed61 100644
--- a/guix-data-service/model/guix-revision-package-derivation.scm
+++ b/guix-data-service/model/guix-revision-package-derivation.scm
@@ -58,7 +58,7 @@ INNER JOIN guix_revision_package_derivations
 WHERE revision_id = $1"
      (list guix-revision-id)))
 
-  (define (get-count-for-next-level system target level-counts)
+  (define (get-count-for-next-level system-id target level-counts)
     (define next-level
       (length level-counts))
 
@@ -73,10 +73,13 @@ WITH l0 AS (
   INNER JOIN guix_revision_package_derivations
     ON package_derivations.id
         = guix_revision_package_derivations.package_derivation_id
-  WHERE revision_id = 19411
-    AND system_id = 4
-    AND target = $STR$$STR$~A
+  WHERE revision_id = ~A
+    AND system_id = ~A
+    AND target = $STR$~A$STR$~A
 )"
+        guix-revision-id
+        system-id
+        target
         (if (= next-level 0)
             ""
             (simple-format