It happened just before 9 p.m. Saturday in Union, causing police to place the restaurant on lockdown.
A father of one of the workers says his son called him in a panic, saying that multiple people wearing masks entered the business.
He also says that several of his coworkers were injured.
Authorities have not yet said how many people were shot, or shared information about their conditions.
There's also no word yet on what led up to the violence.