1)
select *
from employee em
where CONCAT(em.firstname, ' ', em.lastname) like '%parth pa%';
2)
select *
from employee em
where CONCAT_ws('-', em.firstname, em.lastname) like '%parth-pa%';
First is usefull when we have data like : 'firstname lastname'.
e.g
Second is usefull when we have data like : 'firstname-lastname'. In it you can also use special characters.
e.g