rewrite query for mysql compatibility attempt 1

    #min_avg_rank = select([func.min(RouterStats.avg_rank)]).as_scalar()

    max_avg_rank = select([func.max(RouterStats.avg_rank)]).as_scalar()

    # this query breaks MySQL!

    #RouterStats.table.update(values=

    #   {RouterStats.table.c.percentile:

    #        (100.0*RouterStats.table.c.avg_rank)/max_avg_rank}).execute()

    # I think the problem is the reference to RouterStats.table.c.avg_rank -- let's just replace it with the query used above. I think the nested query will be OK

    #query('UPDATE routerstats SET percentile=((%s * routerstats.avg_rank) / (SELECT max(routerstats.avg_rank) AS max_1 \nFROM routerstats))' (100.0,))

    RouterStats.table.update(values=

       {RouterStats.table.c.percentile:

            (100.0*RouterStats.table.c.avg_rank)/max_avg_rank}).execute()

            (100.0*avg_r)/max_avg_rank}).execute()

    tc_session.commit()

  _compute_ranks = Callable(_compute_ranks)