There are some comments code here which might be useful in counting
substrings, or splitting a string into words:

http://dev.mysql.com/doc/refman/5.0/...functions.html

Jens Grivolla wrote:
> Hi,
>
> petersprc@gmail.com wrote:
> > [lots of useful stuff about ft index options]
>
> Ok, I am now inclined to go for boolean matching (which apparently
> counts the number of different matches) and normalize by length
> afterwards. Unfortunately, it doesn't seem to count the number of
> times a term was matched in the document.
>
> Anyway, how can I get the number of words in a string? I couldn't find
> anything like that in the string functions section of the manual.
>
> > If you need more control, you might try using the lucene search engine.
>
> It's not really a natural language document retrieval application, I'm
> just abusing it for my purpose. And I'd really like to be able to work
> directly on our databases.
>
> Thanks for your help.
>
> Ciao,
> Jens