SELECT
  [Contra],
  [Schedule],
SUM(CAST([UsedSM] AS float)) AS [UsedSM],
  SUM(CAST([TotalSU] AS int)) AS [TotalSU],
  SUM(CAST([UsedSU] AS float)) AS [UsedSU],

MatchExpireDate = Case When FIRST_VALUE(Schedule) OVER (PARTITION BY [Contra]
                                                               ORDER BY [Schedule] ASC
                                                               ROWS UNBOUNDED PRECEDING
                                                               ) = [Schedule] Then 'Match'
                                        Else 'Not' End

FROM [dbMartxxx].[dbo].[tblPDPcontracts]

where MatchExpireDate = 'Match'

GROUP BY [Contra],
         [Schedule]

ORDER BY [Contra]  DESC;
GO