獲取每個不同費率名稱的最新費率

Question

RateName     Rate    EffectiveDate
--------     ----    -------------
RateOne      400     2011-01-05
RateOne      410     2011-06-31
RateTwo      147     2010-09-21
RateThree    68      2011-07-14
RateTwo      100     2011-10-30

如果我有上述數據，我如何運行查詢以便將這些作為結果：

RateName     Rate    EffectiveDate
--------     ----    -------------
RateOne      410     2011-06-31
RateThree    68      2011-07-14
RateTwo      100     2011-10-30       

基本上，我只需要每個不同費率名稱的最新費率。

Answer 1

你可以試試這個：

SELECT A.*
FROM YourTable A
INNER JOIN (    SELECT RateName, MAX(EffectiveDate) AS MaxDate
                FROM YourTable
                GROUP BY RateName) B
ON A.RateName = B.RateName AND A.EffectiveDate = B.MaxDate