$sql = "SELECT * FROM
(SELECT o.zipcode, o.city, o.state,
(3956 * (2 * ASIN(SQRT(
POWER(SIN(((z.latitude-o.latitude)*0.017453293)/2),2) +
COS(z.latitude*0.017453293) *
COS(o.latitude*0.017453293) *
POWER(SIN(((z.longitude-o.longitude)*0.017453293)/2),2)
)))) AS distance
FROM zipcoords z,
zipcoords o,
zipcoords a
WHERE z.zipcode = ".$zip." AND z.zipcode = a.zipcode AND
(3956 * (2 * ASIN(SQRT(
POWER(SIN(((z.latitude-o.latitude)*0.017453293)/2),2) +
COS(z.latitude*0.017453293) *
COS(o.latitude*0.017453293) *
POWER(SIN(((z.longitude-o.longitude)*0.017453293)/2),2)
)))) <= ".$radius."
ORDER BY distance) AS random_word_to_silence_that_error
ORDER BY distance ASC LIMIT 0,".$maxresults;
I added random_word_to_silence_that_error
because in your case I suppose it will serve no other purpose.