自己結合を使用したSQLクエリ.

WITH ranked AS (
  SELECT
    *,
    rn = ROW_NUMBER() OVER (PARTITION BY RecId ORDER BY Dt DESC)
  FROM TableA
)
SELECT
  r1.Id,
  r1.Dt,
  r1.Stat,
  r1.RecId
FROM ranked r1
  INNER JOIN ranked r2 ON r1.RecId = r2.RecId AND r2.rn = 1
WHERE r1.Stat = 2

更新 質問の更新後

WITH ranked AS (
  SELECT
    *,
    rn = ROW_NUMBER() OVER (PARTITION BY RecId ORDER BY Dt DESC)
  FROM TableA
)
SELECT
  Id,
  Dt,
  Stat,
  RecId
FROM ranked
WHERE Stat = 2 AND rn = 1