在表中查找相似记录

Question

In a table with employees, I have a situation where for some records a similar record was created that differs by the country of birth (for one record it should always be the United States, for another it will always be a different country). For example:

ID	name	surname	date_of_birth	country_of_birth	department_id
1	Anna	Smith	11/01/1969	United States	1
177	Anna	Smith	11/01/1969	Argentina	1

I would like to find the name of such employee who has such records. I have tried such SQL (which is bad), but it does not return me any records.

Select e1.name,e1.surname from employees.employee e1, employees.employee e2
where e1.name = e2.name
and e1.surname = e2.surname
and e1.country_of_birth <> e2.country_of_birth 

Please give me a hint on how to write the query properly

Answer 1

Use cross join without condition and use departament_id if you need it. Also you have a typo on the conditions. And you would know the Id's

Select e1.Id, e2.Id, e1.name,e1.surname from employees.employee e1
cross join employees.employee e2
where e1.name = e2.name
and e1.surname = e2.surname
and e1.country_of_birth <> e2.country_of_birth 
and e1.departament_id = e2.departament_id

If you wanna filter only those case that you know are only outside of US:

 Select e1.Id, e2.Id, e1.name,e1.surname from employees.employee e1
    cross join employees.employee e2
    where e1.name = e2.name
    and e1.surname = e2.surname
    and e1.country_of_birth <> e2.country_of_birth 
    and e1.departament_id = e2.departament_id
    and e2.country_of_birth <> 'United States'