Do I need to apply for a visa if I connect flight from T3 to T2 at Beijing Capital Airport?

Hi, I wonder:
Do I need a VISA to China, If I have booked a ticket from Oslo - Beijing and then Beijing to Bangkok? And the flight arrive and leave some hours apart? And what if my flight arrives at T3 and my ongoing flight departures from T2 or T1, is it still okay to not apply for a visa?