feat: 优化代码

app/src/main/java/io/legado/app/data/dao/BookDao.kt

@@ -18,9 +18,6 @@ interface BookDao {
     @Query("SELECT * FROM books WHERE origin = '${BookType.local}'")
     fun observeLocal(): LiveData<List<Book>>
 
-    @Query("SELECT * FROM books WHERE (`group` & (SELECT sum(groupId) FROM book_groups)) > 0")
-    fun observeNoneGroup(): LiveData<List<Book>>
-
     @Query("SELECT bookUrl FROM books WHERE origin = '${BookType.local}'")
     fun observeLocalUri(): LiveData<List<String>>