Video shows the suspect attacked a worker at the Castor Bar on the 6400 block of Castor Avenue Tuesday morning.
The man allegedly walked in carrying a gun, but put it away when he saw the female worker.
He then asked to use the restroom and a few minutes later walked out with a knife.
The man then struggled with the victim and cleaned out the cash register.
The worker was not hurt.
Anyone with information is asked to contact Philadelphia Police at 215-686-TIPS (8477), text a tip to PPD TIP (773847) or through PhillyPolice.com.