MySQL query. Cannot do WHERE on alias... alternative??

Question

I want to do the following query:

SELECT getDistance(lat1, lng1, lat2, lng2) as `distance`, `forename`, `surname`, `etc..`
WHERE `distance` < 10
ORDER BY `distance` ASC

Obviously it won't work because you cannot do WHERE clauses on column 'alias'... can anyone help with an alternative??

getDistance() is a custom procedure... this returns the distance in miles between 2 sets of coordinates. (it is a implementation of http://en.wikipedia.org/wiki/Great-circle_distance)...

Many thanks.

Answer 1

SELECT  *
FROM    (
        SELECT getDistance(lat1, lng1, lat2, lng2) as `distance`, `forename`, `surname`, `etc..`
        ) q
WHERE   `distance` < 10
ORDER BY
        `distance` ASC

Answer 2

you could do this, althought it is probably going to slow something up depending on how much action happens in the getDistance sub...

SELECT getDistance(lat1, lng1, lat2, lng2) as `distance`, `forename`, `surname`, `etc..`
WHERE getDistance(lat1, lng1, lat2, lng2) < 10
ORDER BY `distance` ASC