SOQL & Custom relationships

Question

I'm trying to understand how to query using relationships, I'm facing an issue I don't understand,

Here is what I'm trying to resolve :

I'm trying this, but it seems to be wrong.. Can you help me ?

I can't see any Certification__r object in my environment ... Is that why I got this issue :

                          Certification_Attempt__c.Certification__r.id
                          ^ 

Didn't understand relationship 'Certification__r' in field path. If you are attempting to use a custom relationship, be sure to append the '__r' after the custom relationship name. Please reference your WSDL or the describe call for the appropriate names.

If you have an idea, I'm lost...

Thanks

Edit : A Schema Builder picture.. Doesn't it show there is no relation between the Certification, and the attempt ?

------------FINAL EDIT - PROBLEM SOLVED ------------

Ok, there is plenty of things I didn't understand well, and I've been able to understand reading docs and working on it ;

I'll post my work for next people having troubles with this to understand, hope it will help !

First, I didn't look so well to the Certification Application Schema and to the Schema Builder :

And my query and the results :

Thanks to you, helpers !

Answer 1

You have to understand child-to-parent relationships on queries. Check this article for further understanding.

Do you have a Certification__c custom object on the org, which is as a parent of Certification_Attempt__c, right? If so then you have to make just:

Certification__r.id on the query.

EDIT

You have also to remove from query the Certification_Attempt__c field from query, as you already are querying that object.

The full correct query would be:

List<Certification_Attempt__c> oldCertAttempts = [Select Id, Name, Certification_Element__r.Id, Certification_Element__r.Name, Contact.Name, Contact.Account.Name
                                              From Certification_Attempt__c
                                              Where Status__c = 'Scheduled'];

Answer 2

When you use a relationship name in a query, you must use the relationship names without the __c. Instead, append an __r (underscore underscore r).

See the relevant sfdc help page:

https://developer.salesforce.com/docs/atlas.en-us.soql_sosl.meta/soql_sosl/sforce_api_calls_soql_relationships_and_custom_objects.htm

This means the __r is probably correct but you need to remove the Certification_Attempt__c. prefixes as you don't need to specify the object name for each field.

Answer 3

I think its

   Certification_Attempt__r.certification__c

If certification attempt is a child and certification is parent

You can access certification name like this

Certification_Attempt__r.certification__r.Name

Please check below posts:

https://developer.salesforce.com/docs/atlas.en-us.soql_sosl.meta/soql_sosl/sforce_api_calls_soql_relationships.htm