SQL: SET column1+=value

[eluser]Volkof[/eluser]
Hi everyone,

I'm wondering if there is a way to do this:

Code:

$sql = "UPDATE Review
  SET numHelpful +=".$numHelpful.", numNotHelpful +=".$numNotHelpful."
  WHERE reviewID =".$reviewID;

Basically what is happening is that i'm creating a voting system. If user click 'isHelpful', then in DB the column value will be incremented by 1. Same goes for 'NotHelpful'.

I was wondering if you can straight away += into database, rather than get from DB, increment by 1, then update back in. But apparently the former method doesnt work.