How to access a lookup field through SOQL in salesforce?

Question

3 Standard Objects: A, B, C

1. A has a field f1 lookup with B object.
2. B has a field f2 lookup with C object.
3. C has a field f3 which is a text.

How to access f3 field value through Object A?

Answer 1

Assuming A, B and C are standard objects, and f1, f2, f3 are standard fields; and all of them are API names, your SOQL query would look something like:

SELECT f1.f2.f3 FROM A

If A, B and C are custom objects, and f1, f2 and f3 are custom fields; and again all of them are API names, it would look like:

SELECT f1__r.f2__r.f3__c FROM A__c

Also remember to add some kind of WHERE or LIMIT clause to avoid hitting governor limits .

More info on SOQL relationships.