I'm heading to Bangkok next weekend, will be there for 3 days, then head to Cambodia and return to Bangkok from where I'll be taking a flight back to Hyderabad. Please note that the Cambodia to Bangkok and Bangkok to Hyderabad flights are on different airlines and were not booked together.

Will I need to take a second visa when I get to Bangkok from Cambodia (since each one of them only gives you single entry) or can I avoid doing that by remaining in the Bangkok airport before taking my flight to Hyderabad?