在SQL Server 2012中按字符串类型的日期排序

我有一个SQL查询，我在其中检索一些数据，JOINS其中还有一个DateTime字段Delivery，但是在检索时，我将其转换为格式为String的字符串，MMM YYYY但最后我想对整个列表进行排序，Delivery但是当我将该列转换为字符串时， ，我不确定如何按原始DateTime字段对结果进行排序Delivery。我的查询如下

WITH deliveryProducts AS
(
  SELECT DISTINCT FORMAT(a.Delivery,'MMMM yyyy') AS Delivery, b.Product 
  FROM DEALS as a, PRODUCTS as b Where a.TradeDate<=@tradeEndDate
)
, deliveryActuals AS
(
  SELECT
          FORMAT(a.Delivery,'MMMM yyyy') AS Delivery,

          b.Product,COUNT(a.Id) AS Trades, 
          ((6.2898*SUM(a.Volume ))/DAY(EOMONTH(DATEADD(MONTH, DATEDIFF(MONTH, 0,a.Delivery), 0))))*0.001 AS BBLperDay,
          SUM(a.Volume) AS M3,

         SUM(a.Volume*a.Price)/Sum(a.Volume) AS WeightedAverage
FROM     Deals AS a right outer join Products AS b 
           ON a.Product=b.Product AND
           a.TradeDate<=@tradeEndDate
GROUP BY  b.Product,

          DATEADD(MONTH, DATEDIFF(MONTH, 0,a.Delivery),0),  FORMAT(a.Delivery,'MMMM yyyy')

  )

SELECT
  dp.Delivery, dp.Product, trades, BBLperDay, M3, WeightedAverage
FROM
  deliveryProducts dp

  LEFT JOIN deliveryActuals da
    on dp.Delivery = da.Delivery
    and dp.product = da.Product

ORDER BY dp.Delivery,dp.Product

上述查询给我所需要的数据，但通过种种Delivery作为string。

我可以知道解决此问题的更好方法吗？