Here's a somewhat odd SOQL query from the question query user and profile:
select user.id, user.Email,user.FirstName,user.LastName,user.profile.name,user.Username,user.IsActive from user, user.profile
Note that the
FROM clause includes both
Here is a simpler example to follow the Contact to Account relationship:
select Id, Name, Account.Name from Contact, Contact.Account
The same query with the relationship join can be performed with:
Select Id, Name, Account.Name From Contact
Is there any purpose to supporting additional SObject types in the from clause, or is it vestigial?
Is is outlined as supported syntax in SOQL.
SELECT fieldList [subquery][...]
[TYPEOF typeOfField whenExpression[...] elseExpression END][...]
[USING SCOPE filterScope]
Out of interest, if you don't use a valid sObject relationship on the additional sObject types you get the following message:
INVALID_TYPE: Name, Account.Name From Contact, Account ^ ERROR at Row:1:Column:45 A driving SObject type has already been set, all other entity types in the FROM clause must be relationships to the initial object. The driving object is Contact.
While doing some checking I found this old dev forum question that indicated it was added to the syntax in Winter '15. Or at least documented then. - Missing doc for new SOQL multiple object SELECT?