The suspects entered Koreana Plaza at 2370 Telegraph Ave. around 10 p.m. and robbed the business at gunpoint, said Oakland police spokesman Jeff Thomason.
During the robbery, a struggle broke out between the suspects and patrons and employees of the store, Thomason said.
In the course of the melee, one the suspects shot the store's security guard in the foot.
The guard and the patrons managed to detain the suspect who had the stolen money, and arriving officers took him into custody. Investigators were continuing to interview the 24-year-old man this morning, Thomason said.
The two other suspects, including the shooter, remain at large, Thomason said.
The injured security guard was taken to a hospital with injuries that were not life-threatening.