mysql update query query

[helz]

Hello there!
I was just wondering that when you exectute an update query, say:

UPDATE table SET this='that', foo='bar' WHERE id='23'

if i miss out one of the fields of the database table say, in the database theres three columns, but in the query i only change the values of two of them. Does the third remain its value? or is it deleted?

thanks for your time!

[tomhath]

It doesn't change.