[kh99]

You'd want something like this:

UPDATE user SET password=MD5(CONCAT(MD5('XXYYZZ1122'),salt)) WHERE username='User2'

If you want to do it for a primary usergroup, you'd change the WHERE part to

WHERE usergroupid=X

For a secondary usergroup, I think this will work:

WHERE FIND_IN_SET(X, membergroupids) != NULL

If you want to test before doing an actual change, you could do something like

SELECT username FROM user WHERE FIND_IN_SET(X, membergroupids) != NULL

and see what gets selected.

Of course in the above queries you want to replace X with the usergroupid you're interested in.