Query to set all users "Display Usergroup" to Default?

[tfw2005]

Anyone know the syntax for a query to set all users "Display Usergroup" to Default?

This is in relation to the...

AdminCp->User XYZ->Usergroup Options->

Primary is set to X, Display is set to Y. I want Y to revert back to Default, so that the primary will show up on Forum Home HTML markup, etc. Currently, not sure if I did it or not, the display usergroup is almost always set to "registered".

Thanks in advance!

[tfw2005]

Bump, in case this got lost in the holiday shuffle.

Example of what I am looking to do is:

UPDATE user SET reputation = 0

That would be used for resetting reputation.

I am looking to reset the display group for members with multiple usergroups. So something like:

UPDATE user SET displaygroup = 'default'

Not sure if that is right, so if anyone could sound off on what the query to do that is, much appreciated.

Thanks!