Question

I believe i understand joins, left, right innner but I am having a problem with this task. I have to show records that dont match in the second table.

Like if you are an employee, and the employee_phone table doesn’t have a record matching you, what sort of query should I use?

I need to find all the employees who don’t have a match in the employee_phone table.

Answer 1

select * 
from employee
where id not in (select emp_id from employee_phone)

or

select e.* 
from employee e
left outer join employee_phone ep on e.id = ep.emp_id
where ep.emp_id is null