IF  EXISTS (Select 1 from tempdb.sys.objects o where o.object_id = object_id('tempdb..#DateTest'))
BEGIN
DROP TABLE #DateTest
END
 
BEGIN
CREATE TABLE #DateTest(
       [GeneralID] [int] NOT NULL,
       [PeriodNumber] [smallint] NULL,
       [FiscalYearStartDate] [date] NULL,
       [MonthEndDate] [date] NULL,
       [FiscalYear] [smallint] NULL
) ON [PRIMARY]
END
GO
INSERT INTO #DateTest ([FiscalYearStartDate], [MonthEndDate], [GeneralID], [PeriodNumber], [FiscalYear])
VALUES ('2012-12-25', '2013-01-25', 1, 1, 2013)
      , ('2012-12-25', '2013-02-22', 1, 2, 2013)
      , ('2012-12-25', '2013-03-25', 1, 3, 2013)
      , ('2012-12-25', '2013-04-24', 1, 4, 2013)
      , ('2012-12-25', '2013-05-24', 1, 5, 2013)
      , ('2012-12-25', '2013-06-24', 1, 6, 2013)
      , ('2012-12-25', '2013-07-25', 1, 7, 2013)
      , ('2012-12-25', '2013-08-26', 1, 8, 2013)
      , ('2012-12-25', '2013-09-24', 1, 9, 2013)
      , ('2012-12-25', '2013-10-25', 1, 10, 2013)
      , ('2012-12-25', '2013-11-21', 1, 11, 2013)
      , ('2012-12-25', '2013-12-24', 1, 12, 2013)
      , ('2013-01-01', '2013-01-25', 2, 1, 2013)
      , ('2013-01-01', '2013-02-22', 2, 2, 2013)
      , ('2013-01-01', '2013-03-25', 2, 3, 2013)
      , ('2013-01-01', '2013-04-24', 2, 4, 2013)
      , ('2013-01-01', '2013-05-24', 2, 5, 2013)
      , ('2013-01-01', '2013-06-24', 2, 6, 2013)
      , ('2013-01-01', '2013-07-25', 2, 7, 2013)
      , ('2013-01-01', '2013-08-26', 2, 8, 2013)
      , ('2013-01-01', '2013-09-24', 2, 9, 2013)
      , ('2013-01-01', '2013-10-25', 2, 10, 2013)
      , ('2013-01-01', '2013-11-21', 2, 11, 2013)
      , ('2013-01-01', '2013-12-31', 2, 12, 2013)

SELECT GeneralID
      ,PeriodNumber
      ,FiscalYearStartDate
      ,MonthEndDate
      ,LAST_VALUE (MonthEndDate) OVER (PARTITION BY GeneralID, FiscalYear
      ORDER BY MonthEndDate ASC) LastValAscYearEndDate --Lists Each MonthEndDate
      ,FIRST_VALUE(MonthEndDate) OVER (PARTITION BY GeneralID, FiscalYear
      ORDER BY MonthEndDate DESC) FirstValDescYearEndDate --Returns Last Month Ending Date for entire year.
      , FiscalYear
FROM #DateTest
ORDER BY GeneralID, FiscalYearStartDate, PeriodNumber

quote:

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If ORDER BY is not specified entire partition is used for a window frame. This applies only to functions that do not require ORDER BY clause. If ROWS/RANGE is not specified but ORDER BY is specified, RANGE UNBOUNDED PRECEDING AND CURRENT ROW is used as default for window frame. This applies only to functions that have can accept optional ROWS/RANGE specification. For example, ranking functions cannot accept ROWS/RANGE, therefore this window frame is not applied even though ORDER BY is present and ROWS/RANGE is not.

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