DELETE or UPDATE to get NULL value

[anthill]

Hi

I think this is very simple but i can't seem to figure it out. I have a database with a column full of NULL values until there is something inserted. Only how do i get it back to a NULL value, do I UPDATE or would deleting the value just return it back to NULL. I've tried:

mysql_query("DELETE col_a FROM table WHERE id='$id'");

and

mysql_query("UPDATE table SET col_a NULL WHERE id='$id'");

neither set it back to NULL. I think i'm doing something seriously wrong.

Cheers

Ant

[devinemke]

UPDATE table SET col_a = NULL WHERE id = '$id'

[anthill]

d'oh, so close!

Cheers man!