just pass the columnName as parameter of YEAR
SELECT YEAR(ASOFDATE) from PSASOFDATE;
another is to use DATE_FORMAT
SELECT DATE_FORMAT(ASOFDATE, '%Y') from PSASOFDATE;
UPDATE 1
I bet the value is varchar with the format MM/dd/YYYY, it that's the case,
SELECT YEAR(STR_TO_DATE('11/15/2012', '%m/%d/%Y'));
LAST RESORT if all the queries fail
use SUBSTRING
SELECT SUBSTRING('11/15/2012', 7, 4)