mysql>
mysql> SET @birth = '1965-03-01';
Query OK, 0 rows affected (0.00 sec)
mysql> SET @target = '1975-01-01';
Query OK, 0 rows affected (0.00 sec)
mysql> SELECT @birth, @target,
-> YEAR(@target) - YEAR(@birth) AS 'difference',
-> IF(RIGHT(@target,5) < RIGHT(@birth,5),1,0) AS 'adjustment',
-> YEAR(@target) - YEAR(@birth)
-> - IF(RIGHT(@target,5) < RIGHT(@birth,5),1,0)
-> AS 'age';
+------------+------------+------------+------------+------+
| @birth | @target | difference | adjustment | age |
+------------+------------+------------+------------+------+
| 1965-03-01 | 1975-01-01 | 10 | 1 | 9 |
+------------+------------+------------+------------+------+
1 row in set (0.00 sec)
mysql>