Denny Schierz wrote in gmane.org.wikimedia.mediawiki:
hi,
how can i delete or disable the user "admin" without losing the pages from user "admin".
there's very little reason to ever actually delete a user, and attempting to do so is likely to cause problems. you can block them (to prevent them from editing) by visiting Special:Blockip and entering the username (you will need to enable $wgSysopUserBans first). alternatively you can change their username using the following SQL:
update low_priority user set user_name='NewUsername' where user_name='OldUsername'; update low_priority user_newtalk set user_ip='NewUsername' where user_ip='OldUsername'; update low_priority cur set cur_user_text='NewUsername' where cur_user_text='OldUsername'; update low_priority old set old_user_text='NewUsername' where old_user_text='OldUsername'; update low_priority archive set ar_user_text='NewUsername' where ar_user_text='OldUsername'; update low_priority ipblocks set ipb_address='NewUsername' where ipb_address='OldUsername'; update low_priority oldimage set oi_user_text='NewUsername' where oi_user_text='OldUsername'; update low_priority recentchanges set rc_user_text='NewUsername' where rc_user_text='OldUsername';
replacing OldUsername and NewUsername appropriately.
cu denny
kate.