DECLARE @Tbl TABLE (
SetId INT,
Id INT,
Premium VARCHAR(1)
)
INSERT INTO @Tbl VALUES (2012, 5, 'Y')
INSERT INTO @Tbl VALUES (2012, 6, 'Y')
INSERT INTO @Tbl VALUES (2013, 5, 'N')
INSERT INTO @Tbl VALUES (2013, 6, 'N')
--Before Update
SELECT * FROM @Tbl
--Something like this is what you need
UPDATE t
SET t.Premium = t2.Premium
FROM @Tbl t
INNER JOIN @Tbl t2 ON t.Id = t2.Id
WHERE t2.SetId = 2012 AND t.SetId = 2013
--After Update
SELECT * FROM @Tbl