SQL Получите последнее из 2 -таков DateTime

SELECT ID,
       CASE WHEN 
              COALESCE(Date1, '1/1/1973') > COALESCE(Date2, '1/1/1973') -- COALESCE is to ensure comparison works when 1 is nullable
         THEN Date1
         ELSE Date2
       END AS MostRecentDate
FROM Table
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