Robbery has a sentencing range of 2, 3 or 5 years in state prison. There can be additional time in significant injury was inflicted, the clerk was restrained (false imprisonment = 16 months, 2 years or 3 years) or moved a substantial distance (kidnap for robbery carries life in prison).
The exact charge and any allegations in the charging document will determine the possible maximum sentence. Without that, the above ranges are just potentials.
Robbery can be punished by 2, 3, or 5 years in state prison, assuming there are no other charges or enhancements alleged.
But note that a judge is not required to sentence someone to prison for robbery. (Again, this could change if certain enhancements are alleged.) A judge may impose probation and order a defendant to serve time in jail (generally up to a year) as a condition of that probation, and as an alternative to a prison sentence.