I have a problem. When I try craft such URL:
I should get 3 columns (trafficSource, users_left, users_right), but I get only two columns (trafficSource, users). Why?
The Metrica API query runner was a community submission, so we can’t do much to fix it if it breaks. In this case, however, the query runner looks fine. If you have questions about using the Metrica API I’d suggest using their support as this forum isn’t the place for such questions.