How to get data via relationships with APIv4?

Question

Wilma has relationship: is campaigner at organisation System Change Not Charity.

How can I get a list of individuals like Wilma and the organisations that they are campaigners for?

I've read the documentation but I can't figure out how I would join on relationship?

I tried this which I thought would at least give me the names of people with that campaigner relationship type, but it gives nothing.

• Entity: Contact
• Action: get

{                                                                                                                                                                                           
    "select": ["display_name"],                                                                                                                                                               
    "where": [                                                                                                                                                                                                                                                                                                                                                        
      ["relationships.relationship_type_id", "=", 15]                                                                                                                                          
    ],                                                                                                                                                                                        
    "limit": 25,                                                                                                                                                                              
    "checkPermissions": false                                                                                                                                                                 
}

Answer 1

Not sure if this is what you're after but works for me; the 'join on' is a bit hidden in the 'Select' box.

CRM.api4('Relationship', 'get', {
  select: ["contact_a.display_name"],
  where: [["relationship_type_id", "=", 5]],
  limit: 25
}).then(function(relationships) {
  // do something with relationships array
}, function(failure) {
  // handle failure
})

Answer 2

For the part about making your first-step example work, use 'contact_a.display_name' instead of display_name.

Also it's missing from your example but it would be 'Relationship', 'get', at the very beginning, so the whole thing, to also get the org, is

$relationships = civicrm_api4('Relationship', 'get', [
  'select' => [
    'contact_a.display_name', 'contact_b.display_name'
  ],
  'where' => [
    ['relationship_type_id', '=', 15],
  ],
  'checkPermissions' => false,
]);