The Tigers (10-7, 3-0), tied atop the Ivy League standings with Harvard, won their fifth straight game.
Princeton won it from beyond the 3-point arc and at the foul line. Bray was 3 of 3 on 3-pointers. Will Barrett (10 points) and Mack Darrow were each 2 for 3 from long range. The Tigers finished 8 for 11 on treys. Columbia (9-9, 1-3) was 4 of 13.
The score was tied 50-50 midway through the second half. But Hummer, who scored 16 points, was 12 of 14 from the free throw line -- including 7 of 8 in the last 4:28. After Columbia cut it to 69-66, Hummer hit 3 of 4 foul shots in the last 0:08 to ice it.
Maodo Lo led Columbia with 16 points.
Leaving early for the NBA is a risky decision. Some players -- Skal Labissiere, Dejounte Murray -- slid in the draft. Some -- Isaiah Taylor, Troy Williams -- weren't drafted at all.
College basketball coaches across the country will hit the recruiting trail hard in July to target the Class of 2017's top prospects. Which players are the nation's top programs targeting?
The Tar Heels could lose Justin Jackson and Kennedy Meeks after next season. Coach Roy Williams has nearly every top-10 2017 prospect on his board.