I'm sorry, I don't follow...
I attempted to follow the manual, and this is what I came up with:
DELETE
forum_categories, forum_threads, forum_replies
FROM
forum_categories fc, forum_threads ft, forum_replies fr
WHERE
ft.categoryID = fc.categoryID AND
fr.threadID = ft.threadID AND
fc.categoryID = 1
I get the error (the table "forum_categories" DOES exist):
#1109 - Unknown table 'forum_categories' in MULTI DELETE
Am I not supposed to put the table names I want to delete rows from after the DELETE part?
If you use the aliases, I'm assuming you need to refer to them as aliases.