Conditional insert or update.

[Paul Halliday]

Hi, 

I have a table that looks something like this:

ip | mac_current | mac_change

now if I have an entry that looks like this

10.0.0.1 | 11:11:11:11:11:11:11 | NULL

If the next time the script runs and the mac has changed, how can I
catch this and put the new MAC into mac_change?

Ultimately, I would also like to roll the values too. For example if
the MAC changes again, put mac_change into mac_current...


Thanks.
-- 

Paul Halliday

"Diplomacy is the art of saying "Nice doggie!" till you can find a rock."