先根据经纬度和距离计算一个矩形，然后筛选经纬度在矩形范围内的数据。

/**
 *
 * @param Select $select            
 * @param string $columnName            
 * @param string $longitude            
 * @param string $latitude            
 * @param int $distance
 *            metre
 * @return string
 */
static function ST_MBRWithinRectangle(Select $select, $columnName, 
    $longitude, $latitude, $distance)
{
    list ($min, $max) = self::rectangle($longitude, $latitude, $distance);
    $where = "$columnName!=PointFromText('Point(0 0)') and $columnName!='' and";
    $where .= " ST_MBRWithin(`$columnName`,ST_GeomFromText('Polygon(($min[0] $min[1],";
    $where .= "$min[0] $max[1],$max[0] $max[1],$max[0] $min[1],$min[0] $min[1]))'))";
    $select->where($where);
}

/**
 * get rectangle longitude and latitude
 *
 * @param float $longitude
 * @param float $latitude
 * @param integer $distance
 *            meter
 * @return array
 */
static function rectangle($longitude, $latitude, $distance)
{
    $radius = 6371 * 1000;
    // latitude boundaries
    $maxlat = $latitude + rad2deg($distance / $radius);
    $minlat = $latitude - rad2deg($distance / $radius);
    // longitude boundaries (longitude gets smaller when latitude increases)
    $maxlng = $longitude +
         rad2deg($distance / $radius / cos(deg2rad($latitude)));
    $minlng = $longitude -
         rad2deg($distance / $radius / cos(deg2rad($latitude)));
    return array(
        array(
            'lng' => $minlng,
            'lat' => $minlat
        ),
        array(
            'lng' => $maxlng,
            'lat' => $maxlat
        )
    );
}