在php mysql中按排名，优先级和日期排序

Question

我正在使用以下查询根据其定义的等级

对行进行排序

select 
   properties.id,
   properties.agency_id,
   properties.created,
   IF(@prev <> properties.agency_id, @cnt := 1, @cnt := @cnt + 1) AS rank, 
   @prev := properties.agency_id,
   properties.refno
   FROM properties
   INNER JOIN agency  ON properties.agency_id = agency.agency_id
   order by agency.priority, rank , properties.created desc

我想根据'created'和agency_id对最新行进行排名。我怎么能实现它????任何帮助将不胜感激。

properties table
id    agency_id    created        refno     sell_price   
1      1001         2013-12-10    A1-1001     1000000
2      1002         2013-12-09    A2-1002     5000000
3      1001         2013-12-20    A3-1001     9000000
4      1001         2013-12-21    A4-1001     7000000
5      1002         2013-12-25    A5-1002     6500000
6      1003         2013-12-26    A6-1003     5600000

（http://sqlfiddle.com/#!9/84c0b/1/0）

现在我想在创建的列上对它们进行排序，并根据agency_id对它们进行排名。然后想根据agency.priority对它进行排序。我已在代理商表中定义了优先级。如下

 id      agency_id      created        refno     sell_price
           1001        2013-12-21
           1002        2013-12-25
           1003        2013-12-26
           1001        2013-12-20
           1002        2013-12-09 
           1001        2013-12-10