CREATE TABLE TEST1
(
	check_point varchar2(10)
);

insert into TEST1 values ('100mm');
insert into TEST1 values ('500mm');
insert into TEST1 values ('250mm');

CREATE TABLE TEST11
(
	base_check_point varchar2(10)
);

insert into TEST11 values ('100mm');
insert into TEST11 values ('500mm');
insert into TEST11 values ('250mm');

select  count(distinct check_point)
from    test1;

o/p -> 3

select  count(distinct base_check_point)
from    test11;

o/p -> 3


select  count(1)
from(
        select   * from test11
        INTERSECT
        select  * from test1
     )

o/p -> 3