Using a SQL correlated sub-query with exists operator

Question

I'm trying to find all records in the job_history table with their department_ID is not the same as department_id in employees table by using a correlated sub-query with exists operator, however, I'm getting the error code:

ORA-00933: SQL command not properly ended

Can someone tell please tell me what I'm doing wrong based on the schema and code below?

Select * 
from Job_History as J 
where Exists(Select * from hr.Employees e where e.Department_ID != J.Department_ID);

Answer 1

Here:

from Job_History as J 

Oracle does not support keyword as to alias a table (it is supported in column aliases only).

You also most probably want a correlation clause on the employee_id in the subquery.

So:

select * 
from job_history j 
where exists (
    select 1 
    from hr.employees e 
    where e.employee_id = j.employee_id and e.department_id <> j.department_id
);