Store locator vs SQL

I'm trying to build a store locator for gas stations with google maps api. I've done everything as described here (http://code.google.com/apis/maps/articles/phpsqlsearch.html), but

1. The search for address function does not recognize most of the input (I can live with that)
2. The SQL statement as provided by google does not return any results (I've checked that by substituting the statement with "SELECT * FORM marke开发者_如何学运维rs", which works)

My DB table looks like

ID 
NAME
ADDRESS
LAT
LNG

and the statement I'm having troubles with is:

$query = sprintf("SELECT name, address, lat, lng ( 6371 * acos( cos( radians('%s') ) * cos( radians( lat ) ) * cos( radians( lng ) - radians('%s') ) + sin( radians('%s') ) * sin( radians( lat ) ) ) ) AS distance FROM markers HAVING distance < '%s' ORDER BY distance LIMIT 0 , 5",
  mysql_real_escape_string($center_lat),
  mysql_real_escape_string($center_lng),
  mysql_real_escape_string($center_lat),
  mysql_real_escape_string($radius));
$result = mysql_query($query);

which gets its values from the address search.

Does anybody have experience with this or a similar problem?

edit: found the first error: i missed out a comma between lng and (6371... if I insert this directly in phpmyadmin (substituting '%s' with real values) i get the result i want, so I suppose the problem is passing the variables into SQL; hope that helps narrowing it down.

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You need to pass in floats instead of strings, so your php should be

$query = sprintf("SELECT name, address, lat, lng, ( 6371 * acos( cos( radians(%f) ) * cos( radians( lat ) ) * cos( radians( lng ) - radians(%f) ) + sin( radians(%f) ) * sin( radians( lat ) ) ) ) AS distance FROM markers HAVING distance < %d ORDER BY distance LIMIT 0 , 5",
  mysql_real_escape_string($center_lat),
  mysql_real_escape_string($center_lng),
  mysql_real_escape_string($center_lat),
  mysql_real_escape_string($radius));
$result = mysql_query($query);