sugeest on this query

Question

select e.empno,e.empname,e.department,e.designation,r.periodofleavefrom,r.perodofleaveto,r.noofdays from Employee_registration e,Restricted_leaves r where e.empno=r.empno
hi the above query is working fine but it is retrieving multiple records from tabe so i wnat to give the condition  empno='emp1';
where and how to put this condition