SQL-based search engine

Hi!

I've got a problem with a search engine I'm creating. I'm using MySQL, and have got three tables which looks roughly like this (you should have fixed font size to read this);

tblArticle      tblArticlKeyword      tblKeyword
----------      ----------------      ----------
ArticleID  <--> ArticleID         +-> KeywordID
Date            KeywordID <-------+   Keyword

Preferably, I would like my search engine to accept multiple words, and thereafter sort the result on relevance (ie. the articles with most of the keywords in it will be listed first).

MySQL don't support nested queries, unfortunately (though the coming version will), so I need to solve this the hard way for now.

Speed is of great importance here, as the tables consists of the following number of records;

   tblArticle ......:    160,000
   tblArticleKeyword: 13,000,000
   tblKeyword ......:    500,000

Any help will be appreciated, and please excuse my bad English. It's not my primary language.

Please answer in this newsgrup, or - alternatively - send an Email to tore_at_extend.no.

Thanks in advance!

-- 
Tore Aursand - tore_at_extend.no - http://www.extend.no/~tore/