SQL for checking duplicate rows

SELECT        ROLL_NO, REGNO, BOARD_NAME, PASS_YEAR, COUNT(1) as CNT
FROM         BOARD.BOARD_RESULT_DATA
GROUP BY    ROLL_NO, REGNO, BOARD_NAME, PASS_YEAR
HAVING        COUNT(1) > 1;

Another Process


Select ROLL_NO, REGNO, PASS_YEAR, BOARD_NAME
       , count(*) as Occurrences
from BOARD.BOARD_RESULT_DATA
HAVING count(*) > 1
group by ROLL_NO, REGNO, PASS_YEAR, BOARD_NAME