I'm assuming this requires custom php but is it possible to have a GF dropdown populate from a lookup on another table in the WP database?
I'm assuming this requires custom php but is it possible to have a GF dropdown populate from a lookup on another table in the WP database?
Yes, this is possible. It would take custom PHP and the use of a hook to do so.
See this thread which touches on pre-populating a drop down field, in this case a list of states:
http://forum.gravityhelp.com/topic/drop-down-value-different-than-content-text