code: protected QueryBuilder rawQueryOnManyTables(@Nullable final Iterable<String> tables,
        @NonNull final String sql) {
      return new QueryBuilder(tables, sql);
    }
docs: Creates a raw query and enables auto updates for the given tables
  
  @param tables The affected table. updates get triggered if the observed tables changes. Use
  {@code null} or
  {@link #rawQuery(String)} if you don't want to register for automatic updates
  @param sql The sql query statement
  @return Observable of this query