this will work:
create table table_date(dd date);
insert into table_date values(trunc(sysdate));
insert into table_date values(trunc(sysdate)+1);
insert into table_date values(trunc(sysdate)+2);
insert into table_date values(trunc(sysdate)+9);
insert into table_date values(add_months(trunc(sysdate),-5));
//inserting more of them
alter session set nls_date_format = 'dd/MON/yyyy hh24:mi:ss';
SELECT * FROM table_date order by dd;
11/MAY/2018 00:00:00
11/JUL/2018 00:00:00
11/OCT/2018 00:00:00
12/OCT/2018 00:00:00
13/OCT/2018 00:00:00
18/OCT/2018 00:00:00
20/OCT/2018 00:00:00
11/JAN/2019 00:00:00
11/MAR/2019 00:00:00
SELECT * FROM table_date where dd>add_months(current_timestamp,1) or
dd<add_months(current_timestamp,-1);
sample output:
11/JAN/2019 00:00:00
11/MAR/2019 00:00:00
11/JUL/2018 00:00:00
11/MAY/2018 00:00:00