php根据经纬度排序，根据经纬度筛选距离段

SQL 语句：select location.* from (select *,round(6378.138*2*asin(sqrt(pow(sin( (36.668530*pi()/180-px_lat*pi()/180)/2),2)+cos(36.668530*pi()/180)*cos(px_lat*pi()/180)* pow(sin( (117.020359*pi()/180-px_lon*pi()/180)/2),2)))*1000)  as distance from bsx_training where (px_state = 1) and (type_id != '') and (((px_lat >= 27.683290277922) and (px_lat <= 45.653769722078)) and ((px_lon >= 105.81826766053) and (px_lon <= 128.22245033947))) order by  distance limit 0,10) location  where (1=1) and (location.distance <= 500)
先忽略上面这条SQL语句。一一解释
根据SQL排序的SQl语句

// lon1当前用户经度 lat1当前用户纬度，lon2 sql的经度字段 lat sql的纬度字段
function distance_sql($lon1,$lat1,$lon2,$lat2)
{
    $sql = "round(6378.138*2*asin(sqrt(pow(sin( ({$lat1}*pi()/180-{$lat2}*pi()/180)/2),2)+cos({$lat1}*pi()/180)*cos({$lat2}*pi()/180)* pow(sin( ({$lon1}*pi()/180-{$lon2}*pi()/180)/2),2)))*1000) ";
     return $sql;
}

这是一个生成根据SQL排序函数代码

接下来下面是设置经纬度范围内的数据

if(I("post.location")){
            // 用户经纬度
            $location = explode(",",I("post.location"));
            $userLon = $location[0];
            $userLat = $location[1];
            // 经纬度筛选
            $location = getAround($userLat,$userLon,1000000);
            $wheres1.=" and (((px_lat >= {$location["minLat"]}) and (px_lat <= {$location['maxLat']})) and ((px_lon >= {$location['minLng']}) and (px_lon <= {$location['maxLng']})))";
             // 经纬度距离筛选
            if(I("post.distance_sort")){
                $distanceSql = ",".distance_sql($userLon,$userLat,"px_lon","px_lat")." as distance";
                $orderBy = " distance";
            }
            if(I("post.km")){
                $kmStr = htmlspecialchars_decode(I("post.km"));
                if(strpos($kmStr,"<") !== false){
                    $km = explode("<",$kmStr);
                    $wheres2 .= " and (location.distance <= {$km[1]})";
                }else if(strpos($kmStr,"-") !== false){
                    $km = explode("-",$kmStr);
                    $wheres2 .= " and ((location.distance >= {$km[0]}) and (location.distance <= {$km[1]}))";
                 }else if(strpos($kmStr,">") !== false){
                    $km = explode(">",$kmStr);
                    $wheres2 .= " and (location.distance >= {$km[1]})";
                }
            }
        }

下面算出经纬度范围内的数据控制函数

/**
 * 
 * @param  $latitude    纬度    
 * @param  $longitude    经度
 * @param  $raidus        半径范围(单位：米)
 * @return multitype:number
 */
function getAround($latitude,$longitude,$raidus)
{
    $PI = 3.14159265;
    $degree = (24901*1609)/360.0;
    $dpmLat = 1/$degree;
    $radiusLat = $dpmLat*$raidus;
    $minLat = $latitude - $radiusLat;
    $maxLat = $latitude + $radiusLat;
    $mpdLng = $degree*cos($latitude * ($PI/180));
    $dpmLng = 1 / $mpdLng;
    $radiusLng = $dpmLng*$raidus;
    $minLng = $longitude - $radiusLng;
    $maxLng = $longitude + $radiusLng;
    return array (minLat=>$minLat, maxLat=>$maxLat, minLng=>$minLng, maxLng=>$maxLng);
}

要实现根据经纬度排序

就直接调用distance_sql(lon1,lat1,lon2,lat2)传入参数 并且as 一个别名例如 as distance， 然后sql语句中 order by 排序 根据 distance排序

如果筛选距离段 1000米-2000米的数据

那就sql语句嵌套sql 

select *.loation from (select *,round(6378.138*2*asin(sqrt(pow(sin( (36.668530*pi()/180-px_lat*pi()/180)/2),2)+cos(36.668530*pi()/180)*cos(px_lat*pi()/180)* pow(sin( (117.020359*pi()/180-px_lon*pi()/180)/2),2)))*1000) as distance) from table  location where (location.distance >= 1000) and (location.distance <= 2000))

如果实现根据最近位置排序sql

select *,round(6378.138*2*asin(sqrt(pow(sin( (36.668530*pi()/180-px_lat*pi()/180)/2),2)+cos(36.668530*pi()/180)*cos(px_lat*pi()/180)* pow(sin( (117.020359*pi()/180-px_lon*pi()/180)/2),2)))*1000) as distance order by distance 

 public function training_list()
    {
        $wheres1 = "(px_state = 1)";
        $wheres2 = " where (1=1)";
  
        $orderBy = " px_id desc";
        if(I("post.location")){
            // 用户经纬度
            $location = explode(",",I("post.location"));
            $userLon = $location[0];
            $userLat = $location[1];
            // 经纬度筛选
            $location = getAround($userLat,$userLon,1000000);
            $wheres1.=" and (((px_lat >= {$location["minLat"]}) and (px_lat <= {$location['maxLat']})) and ((px_lon >= {$location['minLng']}) and (px_lon <= {$location['maxLng']})))";
             // 经纬度距离筛选
            if(I("post.distance_sort")){
                $distanceSql = ",".distance_sql($userLon,$userLat,"px_lon","px_lat")." as distance";
                $orderBy = " distance";
            }
            if(I("post.km")){
                $kmStr = htmlspecialchars_decode(I("post.km"));
                if(strpos($kmStr,"<") !== false){
                    $km = explode("<",$kmStr);
                    $wheres2 .= " and (location.distance <= {$km[1]})";
                }else if(strpos($kmStr,"-") !== false){
                    $km = explode("-",$kmStr);
                    $wheres2 .= " and ((location.distance >= {$km[0]}) and (location.distance <= {$km[1]}))";
                 }else if(strpos($kmStr,">") !== false){
                    $km = explode(">",$kmStr);
                    $wheres2 .= " and (location.distance >= {$km[1]})";
                }
            }
        }
        
     
     
     
      $showNum = 10;
        if(I("post.page")){
            $page = I("post.page");
        }else{
            $page = 1;
        }
        $n = ($page-1)*$showNum;
        $field = "*{$distanceSql}";
        $sql = "select location.* from (select {$field} from bsx_training where {$wheres1} order by {$orderBy} limit {$n},{$showNum}) location {$wheres2}";
        $training = M()->query($sql);
        
       
        dump(M()->getlastsql());die;
     
    }