Query Google Analytics by User ID
Is there a way to query results using the Core Reporting API (v3) and filtering those results by the User ID assuming that it is being sent to Google Analytics properly?
I've googled this question a lot and read a whole bunch of articles but I did not find one place that does that. Moreover, the fact that I cannot see the User ID anywhere in the reporting interface makes me doubt that this is even possible. I'm guessing I will have to dome something similar to what is recommended here in order to do it?
UPDATE
Apparently, the purpose of my question is not very clear as highlighted by Eike's comment below. What I want to do is generate a report for a specific user with a specific Id using the client API and then combine those results with information I have about this user in my system's database to do something as per my business requirements.
Answer
The best place to turn to for such questions is the Dimensions and Metrics Reference. If the dimension you're looking for is not there then you cannot query it or use it in a filter.
The list is really well maintained, so it's not very likely there are as-of-yet undocumented dimensions you could use.
User id is not there.