问按月排序，然后按MonthYear为字符串SQL的年份进行排序。

EN

declare @ActivityYearStart int = 2014
declare @ActivityYear2 int = (@ActivityYearStart + 2)
declare @ActivityYearEnd int = 2015
declare @ActivityYearM1 int = (@ActivityYearEnd - 1)
declare @ActivityMonth int = 1
declare @ActivityMonth1 int = 3

DECLARE @cols AS NVARCHAR(MAX),
    @query  AS NVARCHAR(MAX)  


select @cols = STUFF((SELECT distinct ',' + QUOTENAME((CONVERT(varchar(5), ActivityMonth) + '-' 
                + CONVERT(varchar(5), ActivityYear))) As MonthYear
            FROM Forecast
            WHERE((ActivityYear = @ActivityYearStart)
              AND (ActivityMonth between  @ActivityMonth and 12))
              OR ((ActivityYear between @ActivityYear2 and @ActivityYearM1)
              AND (ActivityMonth between 1 and 12))
              OR ((ActivityYear = @ActivityYearEnd) 
              AND (ActivityMonth between 1 and @ActivityMonth1))
                     AND Category = 'Forecast'
           Group By Category, ID, ActivityMonth, ActivityYear
           Order By SUBSTRING(MonthYear, 1, 2), SUBSTRING(MonthYear, 2, 4)
        FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')


set @query = '  
    SELECT Category, ID, ' + @cols + ' FROM
             (
                SELECT Category, ID, (CONVERT(varchar(5), ActivityMonth) + ''-'' 
                + CONVERT(varchar(5), ActivityYear)) As MonthYear, HoursCharged
                FROM Forecast    
            ) x
            PIVOT 
            (
                Sum(HoursCharged)
                for MonthYear in (' + @cols + ')
            ) p '

execute(@query)