How to query for dublet attributes across entities via datomic.

gistfile1.clj

(defn datomic-group-fds-by-fd-id [fd-v & {:keys [id-fn] :or {id-fn :hash}}]
  (q '[:find ?fd-id (into [] ?fd)
       :in $fd-v
       :where
       [$fd-v ?fd ?fd-id]
       ]
      (maps->rel fd-v [id-fn])))

(defn datomic-get-redundant-files [grouped-fds-by-fd-id & {:keys [id-fn] :or {id-fn :hash}}]
  (q '[:find ?fd-v-g
       :in $fd-v
       :where
       [$fd-v ?fd-id ?fd-v-g]
       ;; the following does not work: [(> (count ?fd-v-g) 1)]
       [(count ?fd-v-g) ?cnt]
       [(> ?cnt 1)]
       ]
     grouped-fds-by-fd-id))

(defn map-and-filter-get-redundant-files [grouped-fds-by-fd-id & {:keys [id-fn] :or {id-fn :hash}}]
  (filter (fn [x-seq] (> (count x-seq) 1))
          (map second grouped-fds-by-fd-id)))

(defn get-redundant-files [fd-v & {:keys [id-fn] :or {id-fn :hash}}]
  (-> fd-v
      (datomic-group-fds-by-fd-id :id-fn id-fn)
      ;;(datomic-get-redundant-files :id-fn id-fn)
      (map-and-filter-get-redundant-files :id-fn id-fn)
      ))