Ordering in queries by sequence of elements in "IN"

Hello All,

I need a query which delivers results in the order I have in the element sequence after "IN".

SELECT aid, cid, vid FROM table WHERE aid IN (5,7,3)

I want to see the resuts of the query submitted in the same order, it means the first row should be with aid 5, the second with aid 7 and the third with 3.

Without "ORDER BY" I get the results in sequence 3, 5, 7.

Please help

Two ways to do this one proprietary, one standard sql.

This one can be done in mysql only and isn't portable to other applications

ORDER BY FIELD(fieldname,5,7,3)

and this one is portable

ORDER BY
CASE
WHEN fieldname = 5 then 0
WHEN fieldname = 7 then 1
WHEN fieldname = 3 then 2
END