[rt-users] Searching for values in a custom field identified by ID?

[tobiasbp]

Hello list.

I'm looking for resolved tickets with the value of 0 in the custom
field called "Invoice no." like this:
$tickets->FromSQL('("CF.{Invoice no.}"=0 AND Status = "Resolved")');

The above works, but I would like to refer to the custom field by its
ID. How should i formulate my search?

I'm running RT 3.8.8.

Regards,
Tobias