Updates with NULL

Hello All,

I was just updating a table in oracle9.2 by hand and bumped into this.

Following seems to be the valid syntax in oracle.

Update foo set somefield=NULL where somefield >9;

Now I am not sure having something equalled with NULL is a good thig logically.
I would say

Update foo set somefield [to] NULL where somefield >9;

sounds much better. Postgresql uses =default expression which is fine.

Is Oracle behaviour correct?