SQL & PL/SQL

Hello Experts.

I have one requirement which i can resolve using anonymous block in plsql. But i want implement it in select query only.
Database: Oracle 11.2.0

select count(*) from emp where name='xyz' and sal=50
if count(*)>0
then
select dept,sector from emp where name='xyz' and sal=50

here i dont have any primary key.

How can i achieve above using sql query not plsql. Here is one sloution which i have got but its not satisfying above requiremnt as i dont have any primary key columns

select toll_number from toll_details
where toll_id =(select toll_id from toll_details where toll_new_id='5263655214' group by toll_id having count(*)>0)

here toll_id is primary key, so used group by. But how to do this in my above requirement as i dont have primary key.

Appreciate any help on this.
Thank you