MySQL大圆距离（Haversine公式）

我有一个工作的PHP脚本，该脚本获取经度和纬度值，然后将它们输入到MySQL查询中。我只想将其制作成MySQL。这是我当前的PHP代码：

if ($distance != "Any" && $customer_zip != "") { //get the great circle distance

//get the origin zip code info
$zip_sql = "SELECT * FROM zip_code WHERE zip_code = '$customer_zip'";
$result = mysql_query($zip_sql);
$row = mysql_fetch_array($result);
$origin_lat = $row['lat'];
$origin_lon = $row['lon'];

//get the range
$lat_range = $distance/69.172;
$lon_range = abs($distance/(cos($details[0]) * 69.172));
$min_lat = number_format($origin_lat - $lat_range, "4", ".", "");
$max_lat = number_format($origin_lat + $lat_range, "4", ".", "");
$min_lon = number_format($origin_lon - $lon_range, "4", ".", "");
$max_lon = number_format($origin_lon + $lon_range, "4", ".", "");
$sql .= "lat BETWEEN '$min_lat' AND '$max_lat' AND lon BETWEEN '$min_lon' AND '$max_lon' AND ";
}

有谁知道如何完全使用MySQL？我浏览了一下互联网，但是关于它的大多数文献都令人困惑。