I use the following select statement that correctly retrieves the data
I want:

SELECT * FROM userpref AS pref
JOIN userpref AS pref2 ON pref2.userid=pref.userid
WHERE ( pref.questionid = '30' and pref.answer = '7507')
and( pref2.questionid = '41' and pref2.answer = '9108' )

The problem is that some of my select statements get rather complicated
and I use a lot of self-joining to the userpref table above, perhaps a
dozen or so self joins. This causes the select statements to really
sloooow down, taking a few minutes in some cases. Since this is used by
a website, this is not a good solution.
I thought I could improve performance if I were to trash the joins
and somehow do all the logic in the WHERE statement as:

SELECT * FROM userpref AS pref
WHERE ( pref.questionid = '30' and pref.answer = '7507')
and ( pref.questionid = '41' and pref.answer = '9108' )

Of course this doens't work, as the same questionid is referenced
twice, but my question is, is there some syntax here that would give
the same result as the join above but without using the join and have
the logic in the where statement alone?
Thanks