A judge on Tuesday tossed the case against city Comptroller Scott Stringer’s brother, who was accused of punching a patron at a posh Upper East Side sushi restaurant last year.

David Stringer, a 57-year-old real estate broker, had been charged with misdemeanor assault for allegedly slugging a 33-year-old man who protested his “treatment of the staff and bartenders” at the Second Avenue eatery near East 73rd Street on Nov. 15, 2019.

Prosecutors told the judge they had no video of the incident or cooperating witnesses — and their several attempts to reach the victim have gone unanswered.

With a judge’s blessing, David Stringer left court before the case was even dismissed.

“Since they were dismissing the case, there was no need for him to stay,” Stringer’s attorney, Stacey Richman, told The Post.