18th October 2018: PostgreSQL 11 Released!
Unsupported versions: 7.1

4.8. Updates

You can update existing rows using the UPDATE command. Suppose you discover the temperature readings are all off by 2 degrees as of Nov 28, you may update the data as follow:

UPDATE weather
    SET temp_hi = temp_hi - 2,  temp_lo = temp_lo - 2
    WHERE date > '1994-11-28';