Help in Update Query

Question

Hi, I want to update status_code of table_2. T_ID is the primary key in both table (Table_1 and table_2). The condition is any person's age >70 then status_code should be 'R' and if person's age<70 then status_code should be 'N'. Please help on this
Update query.
/*Table_1*/
T_ID  LASTNAME  FIRSTNAME   DOB
1001 KAISER      SUJIR    01/01/1942
1002 SMITH     HUJR       01/01/1948
1003 JOHN      JANE       02/01/1958
/*Table_2*/
T_ID  LASTNAME  FIRSTNAME   STATUS_CODE
1001 KAISER      SUJIR    R
1002 SMITH     HUJR       R
1003 JOHN      JANE        R
/*Need the Following Result after the Update*/
T_ID  LASTNAME  FIRSTNAME   STATUS_CODE
1001 KAISER      SUJIR    R   --The Age is >70 that's why status_code is 'R'
1002 SMITH     HUJR       N  --The Age is <70
1003 JOHN      JANE        N  --The Age is <70

Answer 1

DECLARE @table1 TABLE (T_ID INT, lastName VARCHAR(30), firstName VARCHAR(30), dob DATE)
INSERT INTO @table1 (T_ID, lastName, firstName, dob) VALUES (1001, 'KAISER', 'SUJIR' ,'01/01/1942'),(1002, 'SMITH', 'HUJR', '01/01/1948'),(1003, 'JOHN', 'JANE', '02/01/1958'),(1004, 'Jack', 'Jackson', '12/03/1944')
DECLARE @table2 TABLE (T_ID INT, lastName VARCHAR(30), firstName VARCHAR(30), statusCode CHAR(1))
INSERT INTO @table2 (T_ID, lastName, firstName, statusCode) VALUES (1001, 'KAISER', 'SUJIR', 'R'),(1002, 'SMITH', 'HUJR', 'R'),(1003, 'JOHN', 'JANE', 'R'),(1004, 'Jack', 'Jackson', 'R')
-- tables set up
UPDATE @table2
SET statusCode = CASE WHEN DATEDIFF(YEAR,t1.dob,CURRENT_TIMESTAMP) - CASE WHEN DATEADD(YEAR,DATEDIFF(YEAR,t1.dob,CURRENT_TIMESTAMP),t1.dob) > CURRENT_TIMESTAMP THEN 1 ELSE 0 END >= 70 THEN 'R' ELSE 'N' END
FROM @table2 t2
INNER JOIN @table1 t1
ON t2.T_ID = t1.T_ID
SELECT *, DATEDIFF(YEAR,t1.dob,CURRENT_TIMESTAMP) - CASE WHEN DATEADD(YEAR,DATEDIFF(YEAR,t1.dob,CURRENT_TIMESTAMP),t1.dob) > CURRENT_TIMESTAMP THEN 1 ELSE 0 END
FROM @table2 t2
INNER JOIN @table1 t1
ON t2.T_ID = t1.T_ID