Where emp.dept_id=nvl(dept_id,10)(+) conditions is failing,

Question

select empno, ename from emp,dept
where dept.dept_id=emp.dept_id(+)
now
select empno,ename from emp, dept
where dept.dept_id=nvl(emp.dept_id,dept.dept_id)(+)
is throwing error
ORA-00936: missing expression
Can you please suggest how to do it
Thanks,

Answer 1

Dear,
select empno,ename from emp, dept
where dept.dept_id=nvl(emp.dept_id,dept.dept_id)(+)Could you please phrase what you want to get using the above query?
You are telling oralce to join dep to emp using dept_id; and you are also telling oracle that if the dept_id in emp is null then consider the dept.dept_id instaed. So in this case your query will ressemble to the following one
select empno,ename from emp, dept
where dept.dept_id=dept.dept_id(+)And hence you will be outer joinging two tables to each other wich is not possible
Best Regards
Mohamed Houri