Try this
SELECT DISTINCT(`date`) AS date
FROM attendance
WHERE UNIX_TIMESTAMP(`date`)>UNIX_TIMESTAMP('01-01-2014')
AND
UNIX_TIMESTAMP(`date`)<UNIX_TIMESTAMP('24-02-2014')
OR
SELECT date
FROM attendance
WHERE UNIX_TIMESTAMP(`date`)>UNIX_TIMESTAMP('01-01-2014')
AND
UNIX_TIMESTAMP(`date`)<UNIX_TIMESTAMP('24-02-2014')
GROUP BY date