What is the best way to write a SQL query spanning multiple tables?

Question

SQL

Hey! There are the following tables:

_________________________________________________________________________________________________________________________________
people - people
planet - planets
planet_resource - resources that are present on planets
people_planet - comparison of planets and people who have access to
them planet_resource_person - comparison of resources of planets and people who have access to them
As can be seen from the tables , several people can have access to the same planet, but different access to resources is possible, including no access to resources at all.
Attention, question)How to get a list of planets for a certain person on which he has access to at least one resource? For example, Victor has access to Venus and Earth, but at the same time, access to resources is only available on Venus - that is, the result of the query should be a row with id=2 from the planet table.

Answer 1

It is necessary not only to link, but also to isolate unique data without duplication, the DISTINCT instruction will help here :

SELECT DISTINCT
  planet.*
FROM
  planet
INNER JOIN
  planet_resource
ON
  planet_resource.planet_id = planet.id
INNER JOIN
  planet_resource_person
ON
  planet_resource_person.resource_id = planet_resource.id
INNER JOIN
  people_planet
ON
  people_planet.people_id = planet_resource_person.person_id
  AND people_planet.planet_id = planet.id
WHERE
  people_planet.people_id = ID нужного человека

Answer 2

Link JOIN.