$lat = trim($_REQUEST['lat']);
$lng = trim($_REQUEST['lng']);

$lat = (!empty($lat)? $lat : 41.3423502);
$lng = (!empty($lng)? $lng : -73.0774616);

$HelpQuery = sprintf("SELECT *, ( 3959 * acos( cos( radians( %s ) ) * cos( radians( lat ) ) * cos( radians( lng ) - radians( %s ) ) + sin( radians( %s ) ) * sin( radians( lat ) ) ) ) AS distance FROM databaseTable ORDER BY distance LIMIT 0,5",$lat,$lng,$lat);

$HelpResult = mysql_query($HelpQuery);
$result = array();
$result['info'] = "";

if($HelpResult)
{
	while($Helprow = mysql_fetch_assoc($HelpResult))
	{
			$Helprow['distance'] = round($Helprow['distance'],2);
			$result['info'][] = $Helprow; 
	}
}
else
{
	$result['info'] = "Error";
}

Expects databaseTable to have both lat and lon columns with appropriate location coordinate data.

Get closest locations by latitude longitude SQL math statement

PHP