SELECT m1.Column1, m1.Column2, m1.Column3, r.MaxTime FROM ( SELECT Column1, MAX(TimeColumn) as MaxTime FROM MyTable GROUP BY Column1 ) r INNER JOIN MyTable m1 ON m1.Column1= r.Column1AND m1.TimeColumn = r.MaxTime
SELECT m1.Column1, m1.Column2, m1.Column3, r.MaxTime FROM ( SELECT Column1, MAX(TimeColumn) as MaxTime FROM MyTable GROUP BY Column1 ) r INNER JOIN MyTable m1 ON m1.Column1= r.Column1AND m1.TimeColumn = r.MaxTime