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Databases

Erick Amezcua
Erick Amezcua
21,826 Points
Posted by Erick Amezcua
Erick Amezcua
21,826 Points

Traveling through the tables (joins problem)

It's posible with one query make a join to a "distant" table. There is my database diagram: https://imgur.com/a/IjBxv

Can I know in which region an employee works by looking for his name?. Starting in employees table and end in the regions table?

1 Answer

Steven Parker
Steven Parker
229,732 Points
Steven Parker
Steven Parker
229,732 Points

Sure, you just have to dig through the relationships to get there:

SELECT E.first_name, E.last_name, R.region_name
  FROM EMPLOYEES E
  INNER JOIN DEPARTMENTS D ON E.department_id = D.department_id
  INNER JOIN LOCATIONS L ON D.location_id = L.location_id
  INNER JOIN COUNTRIES C ON L.country_id = C.country_id
  INNER JOIN REGIONS R ON C.region_id = R.region_id
-- the next line is optional, without it you get the region for ALL employees
  WHERE E.employee_id = --{ID of the one you want}

Now please tell me I didn't just do your homework. :open_mouth:

Erick Amezcua
Erick Amezcua
21,826 Points
Erick Amezcua
Erick Amezcua
21,826 Points

Actually yes, but now it all makes sense, I did not know that a join could be made after a join. Thank you so much