插入CURRENT_TIME减去1小时？

I have a database table with a timestamp column named "lastfed".

Does someone know how I can update that column with current time minus for example 1 hour?

$query = $db->prepare("UPDATE test SET fullness = $newFullness, lastfed = CURRENT_TIME WHERE id = ?");

Use date_sub()

UPDATE test 
SET fullness = $newFullness, 
    lastfed = date_sub(now(), INTERVAL 1 HOUR) 
WHERE id = ?

sqlfiddle demo

UPDATE test 
SET fullness = $newFullness, lastfed = SUBDATE(CURDATE(), INTERVAL 1 HOUR) WHERE id = ?