create table matable ( madate date, section character(50) );

insert all into matable (section, madate) values ('500', to_date('08/12/2018','DD/MM/YYYY')) into matable (section, madate) values ('500',to_date('12/09/2020','DD/MM/YYYY')) into matable (section, madate) values ('400',to_date('25/04/2015','DD/MM/YYYY')) into matable (section, madate) values ('400',to_date('26/07/2019','DD/MM/YYYY')) into matable (section, madate) values ('300',to_date('10/10/2020','DD/MM/YYYY')) into matable (section, madate) values ('300',to_date('02/12/2018','DD/MM/YYYY')) select 1 from dual;

select section, max(madate) as madate from matable group by section;