Depends greatly on the dog. Some require lots of attention and will go nuts without you. Others are perfectly fine on their own. Many will just sleep all day if you're not there, and as long as you give them attention at night, it'll be fine.
But they need to be let out to walk and go to the bathroom every 6 hours or so. Bare minimum 2-3 times a day. I have an inside dog, and I come home during my lunch break to walk him.
ETA: If he's not already housebroken, you're really gonna wanna do that before you leave him alone. Like get him when you have time off so you can train him.
This post was edited on 1/24 at 10:08 pm