how to check two tables by row by row ?if secound table having old record it should be updated ?

Use BINARY_CHECKSUM

Suppose you have PrimaryKey Column(or any Unique column) on two tables, let's say Id

SELECT T1.*
FROM
(
SELECT *, CAST(BINARY_CHECKSUM(*) AS BIGINT)  AS BCHECKSUM
FROM Table1
--WHERE Id IN(.,.,..) -- To be used in subsequent iteration
)AS T1
LEFT OUTER JOIN
(
SELECT Id, CAST(BINARY_CHECKSUM(*) AS BIGINT) AS BCHECKSUM
FROM Table2
--WHERE Id IN(.,.,..) -- To be used in subsequent iteration
)AS T2
ON T1.Id = T2.Id
WHERE T1.BCHECKSUM <> T2.BCHECKSUM

Now you have unmatched rows... Note down Ids for unmatched and continue with BINARY_CHECKSUM(Col1, Col2, ..., Coln) (i.e. initially we used *, now we select specific columns to narrow down unmatch to specific column's row) on the above(but it restrict to the Ids that are not matching) script and keep on removing each column in step until you see BINARY_CHECKSUM is same.