Prova questo
select * from `table` where `yourfield` >= DATE_SUB(CURDATE(), INTERVAL 3 MONTH)
Per giorni, anno vedi ad esempio sotto.
DATE_SUB(CURDATE(), INTERVAL 15 DAY) /*For getting record specific days*/
DATE_SUB(CURDATE(), INTERVAL 1 YEAR) /*for getting records specific years*/
Per Anand, interroga
BETWEEN DATE_SUB( CURDATE( ) ,INTERVAL 6 MONTH ) AND DATE_SUB( CURDATE() ,INTERVAL 3 MONTH )
/* For Getting records between last 6 month to last 3 month
