Select all parents having a child with specific property

Question

Consider the following pseudo tables:

Parent(id)
Child(id, parent_id, property)

How can I select all parents having a child where property has a specific value in PostgreSQL?

Answer 1

You can use exists:

select p.*
from parent p
where exists (select 1
              from child c
              where c.parent_id = p.id and c.property = ?
             );