MySQL Table Join

[suit4]

hi everybody,

can somebody give me hint about this?

i have two tables:
table 'words' with 'WordID' and 'Word'
(8000 entries)
and
table 'wordsindocuments' with 'WordID' and 'DocumentID' (about 50.000 entries)

what i want to do is:
find all words (from 'words') which are NOT present in 'wordsindocuments'

i tried this:

SELECT STRAIGHT_JOIN t0.WordID
FROM words t0,wordsindocuments t1
WHERE t1.WordID is NULL

but there is no result (but there has to be a result, because i removed some of the WordID's in 'wordsindocuments'

when i use this:

select words.* from words
LEFT JOIN wordsindocuments ON words.WordID=wordsindocuments.WordID
where wordsindocuments.WordID is NULL;

i get a massive cpu load, my system gets extremely slow and i have to kill mysql-process to continue my work.

any ideas?

thanks

[bogu]

Are your table tide together.

[bogu]

This is the first idea that I have in mind, I know that is not the best but it should work.

$id='';
while($rez=mysql_fetch_assoc(mysql_query('SELECT wordsid AS id FROM wordsindocuments')))
$id.=$rez['id'].',';
$id=substr($id,0,-1);
$words=array();
while($rez=mysql_fetch_assoc(mysql_query('SELECT wordsid AS id,words FROM words WHERE wordsid NOT IN('.$id.')')))
$words[$rez['id']]=$rez['words'];

If I will have another idea I'll write you.