Return comment count for main thread and all reply threads for one url.

def reply_count(self, url, mode=5, after=0):
        """
        Return comment count for main thread and all reply threads for one url.
        """

        sql = ['SELECT comments.parent,count(*)',
               'FROM comments INNER JOIN threads ON',
               '   threads.uri=? AND comments.tid=threads.id AND',
               '   (? | comments.mode = ?) AND',
               '   comments.created > ?',
               'GROUP BY comments.parent']

        return dict(self.db.execute(sql, [url, mode, mode, after]).fetchall())