WITH snapshotWithTies AS (SELECT s.PlayerId, s.S

WITH snapshotWithTies AS
  (SELECT s.PlayerId,
          s.Score,
          s.[DATE]
   FROM dbo.[Snapshot] s
   GROUP BY s.PlayerId,
            s.Score,
            s.[DATE]),
     firstDateScoring AS
  (SELECT TOP 1 WITH TIES *
   FROM snapshotWithTies snap
   WHERE [DATE] >= '2020-01-08'
   ORDER BY ROW_NUMBER() OVER(PARTITION BY snap.PlayerId
                              ORDER BY snap.[DATE] ASC)),
     secondDateScoring AS
  (SELECT TOP 1 WITH TIES *
   FROM snapshotWithTies snap
   WHERE [DATE] <= '2020-01-09'
   ORDER BY ROW_NUMBER() OVER(PARTITION BY snap.PlayerId
                              ORDER BY snap.[DATE] DESC))
SELECT p.Id Id,
       p.[Username] Player,
       ss.Score - fs.Score Delta
FROM dbo.[Player] p
JOIN firstDateScoring fs ON fs.PlayerId = p.Id
JOIN secondDateScoring ss ON ss.PlayerId = p.Id;