Create the read (COPY TO) query

def _get_read_query(self, table_columns, limit=None):
        """Create the read (COPY TO) query"""
        query_columns = [column.name for column in table_columns]
        query_columns.remove('the_geom_webmercator')

        query = 'SELECT {columns} FROM "{schema}"."{table_name}"'.format(
            table_name=self.table_name,
            schema=self.schema,
            columns=', '.join(query_columns))

        if limit is not None:
            if isinstance(limit, int) and (limit >= 0):
                query += ' LIMIT {limit}'.format(limit=limit)
            else:
                raise ValueError("`limit` parameter must an integer >= 0")

        return query