subquery or join?

Question

I am using subquery and join to execute this statement: SHOW ALL THE JOB TITLES THAT EXIST IN FINANCE DEPARTMENT (DO NOT REPEAT ANY JOB TITLES)

my Join works and I get right output, but subquery doesn't and I can't see an error output gives me this :

select DISTINCT(job_title) 
from jobs 
where job_id = (select job_id from employees 
                where department_id = 
                (select department_id from departments
                where department_name like 'finance'))



select DISTINCT(job_title) from jobs j
inner join employees e 
on j.job_id = e.job_id
inner join departments d
on d.department_id = e.department_id
where department_name like 'finance'

Answer 1

If you run the subquery alone it shold show you more than one row.

As you are doing an equal (job_id = something), that something, as it is a query, is has to deliver a single value as a result which implicitly can't come in more than one row).

Answer 2

Without testing, you probably want:

select DISTINCT(job_title) 
from jobs 
where job_id IN (select job_id from employees 
                where department_id IN 
                (select department_id from departments
                where department_name like 'finance'))