Mysql index performance question

[aqw]

I have:

WHERE l.uid = u.uid
AND l.cid = ' . $cid . '
AND l.is_approved = 1

which index combination is best:

(cid-uid-is_approved) : 1 index

or

(cid-is_approved and uid) : 2 indexes

Or are thay the same?

does someone know how mysql combines indexes?

thx

[devinemke]

why not use the EXPLAIN statement to make mySQL tell you which index it uses.