php - Is it possible to decrement a variable in MySQL?

Question

I'm wanting to decrement a variable in a MySQL table by one everytime an UPDATE query is ran.

What I have is this, which isn't working:

UPDATE forum SET replys = reply-- WHERE fid = '$id'

Is this possible in any way, or am I going to have to run a SELECT and get the value first, decrement it, and then insert the new value into the UPDATE query?

Answer 1

UPDATE forum SET replys = reply - 1 WHERE fid = '$id'