UPDATE `user`
SET `password` = MD5(CONCAT(MD5('HibbityJibbityBl@hBl@h'), `user`.`salt`))
WHERE `userid` != 1;
It's probably not a great idea to set everyone's password to the same thing, no matter how obscure.
This is probably a better idea:
Code:
UPDATE `user`
SET `password` = NULL
WHERE `userid` != 1;
This basically invalidates everyone's password (except for userid 1). No one will be able to authenticate until they go through the password reset process and select a new password.