DECLARE @SampleData
TABLE   (
        id          INTEGER NOT NULL,
        first       INTEGER NOT NULL,
        sec         INTEGER NOT NULL,
        group_id    INTEGER NOT NULL,
        vid         INTEGER NOT NULL,
        
        PRIMARY KEY CLUSTERED (id)
        );

INSERT  @SampleData
VALUES  (1, 1, 2, 16, 122),
        (3, 2, 1, 16, 122),
        (2, 3, 1, 08, 033),
        (4, 1, 5, 16, 012),
        (5, 1, 6, 16, 001);

SELECT  *
FROM    (
        SELECT  *,
                row_num = 
                    ROW_NUMBER() OVER (
                    PARTITION BY S.group_id 
                    ORDER BY S.first * S.sec ASC)
        FROM    @SampleData S
        ) S
WHERE   S.row_num = 1;

DECLARE @SampleData
TABLE   (
        id          INTEGER NOT NULL,
        first       INTEGER NOT NULL,
        sec         INTEGER NOT NULL,
        group_id    INTEGER NOT NULL,
        vid         INTEGER NOT NULL,
        computed    AS ISNULL(first * sec, 0)
        
        PRIMARY KEY CLUSTERED (id)
        );

INSERT  @SampleData
VALUES  (1, 1, 2, 16, 122),
        (3, 2, 1, 16, 122),
        (2, 3, 1, 08, 033),
        (4, 1, 5, 16, 012),
        (5, 1, 6, 16, 001);

SELECT  S.id, S.group_id, S.computed
FROM    @SampleData S
WHERE   S.computed =
        (
        SELECT  MIN(S2.computed)
        FROM    @SampleData S2
        WHERE   S2.group_id = S.group_id
        );