database - MySQL: Selecting random things starting with a X letter -

i using database: http://www.4redpixels.com/uploads/words.sql

i want select random word starting x (unknown) letter. how can that?

actually, best way words start particular letter use like:

select w.word words w w.word 'x%' order rand() limit 1; 

this can take advantage of index on words(word). in addition, if list long, there better ways random row order rand().