or-join

(xt/query-list xtdb
               '{:find  [(pull b [*])]
                 :where [[b :label :book/book]
                         [(str/lower-case word) word-lower]
                         (or-join [b word-lower]
                                  (and  [b :title title]
                                        [(str/lower-case title) title-lower]
                                        [(str/includes? title-lower word-lower)])
                                  (and [ba :label :book/book-author]
                                       [ba :author-id a]
                                       [ba :book-id b]
                                       [a :name name]
                                       [(str/lower-case name) name-lower]
                                       [(str/includes? name-lower word-lower)]))]
                 :in    [[word ...]]}
               ["제목" "저자"])