The shooting was reported at 6:12 p.m. Saturday in the 500 block of Grove Street near Octavia Street.
The 52-year-old victim and a younger acquaintance were inside the store when two suspects fired into it, apparently targeting the younger male, police spokesman Officer Albie Esparza said.
The younger victim was not hit but the 52-year-old was struck in the right leg by the gunfire. He was taken to San Francisco General Hospital to be treated for his injuries, which are not considered life-threatening, Esparza said.
The suspects, described as two men in their mid 20s who were wearing all-black clothing, had not been found as of this afternoon, according to Esparza.
The younger victim left from the store before officers arrived and has not yet talked to police, Esparza said.
The shooting remains under investigation. Anyone with information about the case is asked to call the Police Department's anonymous tip line at (415) 575-4444 or send a tip by text message to TIP411.