Is it possible to combine two Google Analytics tracking codes into one without losing statistics?

Question

Google Analytics

Given : old site 1 and old site 2. Each has its own Google Analytics tracking code.
Task : put Google Analytics on the new site so that the statistics of the new site include the past statistics of both the old site 1 and the old site 2 (combined).

Is it possible?

Answer 1

https://support.google.com/analytics/answer/103240...

Answer 2

Old statistics cannot be saved, new ones can be collected from all sites at once.

Answer 3

you cannot change the data already received, you can put the code on the old site and install the same code on the new one, but mark the traffic using a custom parameter, for example (in the case when both versions of the site are on the same domain and this user switches designs)