CoreBOSBB

Maybe a silly question, but I just assumed this was not possible: Can we use JOINS in queries made over webservice?

Yes, you can but not the typical SQL join. The application knows how to setup the joins so you basically ask for what you need. For example:

select potentialname,Accounts.accountname from Potentials

it will know how to join potentials and accounts to get the name.

You can find some examples, with the resulting SQL here:

https://github.com/tsolucio/coreBOSTests/blob/master/include/Webservices/VtigerModuleOperation_QueryTest.php#L138