通过关联表在 Laravel 5.1 中的 POINT 上按距离排序

Question

我正在尝试按events 与用户提交的邮政编码和距离的距离来订购。

我附上了我的数据库表及其关系的示例，如您所见，geom 通过postcode 与多个地址相关联，并且地址可以与多个表相关联（在本例中为事件表）。

我从最终用户那里获取邮政编码以及以英里为单位的半径来检索适当的事件，这是我如何在 Eloquent 中实现这一目标的示例。

/**
 * Extend locale method which initially only gets lat/long for given postcode to search
 *
 * @param \Illuminate\Database\Eloquent\Builder $query The query builder
 * @param \App\Http\Requests\SearchRequest $request The search request
 * @return void
 */
protected function locale(Builder $query, SearchRequest $request)
{
    $postcode = $this->formatPostcode($request->postcode);

    $geom = Geom::query()->where('postcode', $postcode)->first();
    if (! $geom || Cache::has('postcodeAPIFailed')) {
        return;
    }

    $lat = $geom->geo_location['lat'];
    $long = $geom->geo_location['long'];

    // Top-left point of bounding box
    $lat1 = $lat - ($request->within / 69);
    $long1 = $long - $request->within / abs(cos(deg2rad($lat)) * 69);

    // Bottom-right point of bounding box
    $lat2 = $lat + ($request->within / 69);
    $long2 = $long + $request->within / abs(cos(deg2rad($lat)) * 69);

    $query->whereHas('address', function (Builder $query) use ($request, $lat, $long, $lat1, $long1, $lat2, $long2) {
        $query->whereHas('geom', function (Builder $query) use ($request, $lat, $long, $lat1, $long1, $lat2, $long2) {
            $query->whereRaw('st_within(geo_location, envelope(linestring(point(?, ?), point(?, ?))))', [$long1, $lat1, $long2, $lat2]);
        });
    });
}

在控制器中检索到搜索结果后，我们计算每个结果的距离。

if ($request->has('postcode')) {
    $postcodeDistances = $this->getDistances($results, $request);
}

这会产生一个带有key of postcode 和value of distance 的数组，即$postcodeDistances['L1 0AA'] = '3';，我们将这个数组发送到视图。

然后在视图中，我们使用以下逻辑在适用的记录上显示距离

@if($postcodeDistances)
    <span>
        {{ $postcodeDistances[$result->address->postcode] }}
        mile{{ $postcodeDistances[$result->address->postcode] != 1 ? 's' : '' }} away
    </span>
@endif

我尝试了几种方法，但无法更新我的function locale() 以按距离进行排序。我考虑过也许我可以将距离附加到集合并使用 Laravel 方法以这种方式对集合进行排序，但如果后者甚至可能的话，从数据库层实现这一点将是理想的。

我的第一次尝试是在whereHas('geom') 之后添加选择距离字段并按新字段排序

$query->addSelect(\DB::raw("ST_DISTANCE_SPHERE(geo_location, POINT({$long}, {$lat})) AS distance"));

我收到以下错误：

SQLSTATE[21000]: Cardinality violation: 1241 Operand should contain 2 column(s) (SQL: select count(*) as aggregate from `event` where (select count(*) from `address` where `address`.`addressable_id` = `event`.`id` and `address`.`addressable_type` = event and (select count(*), ST_DISTANCE_SPHERE(geo_location, POINT(-2.717472, 53.427078)) AS distance from `geom` where `geom`.`postcode` = `address`.`postcode` and st_within(geo_location, envelope(linestring(point(-3.6903924055016, 52.847367855072), point(-1.7445515944984, 54.006788144928))))) >= 1) >= 1 and (select count(*) from `organisation` where `event`.`organisation_id` = `organisation`.`id` and `status` = 1) >= 1 and `event_template_id` is not null and `date_start` >= 2018-07-31 00:00:00 and `status` in (1, 5))

我也尝试在同一个地方使用 orderByRaw，虽然我没有收到错误，但结果没有相应地排序。

$query->orderByRaw('ST_DISTANCE_SPHERE(geo_location, POINT(?, ?)) ASC', [$long, $lat]);

Answer 1

我会尽力解决您的问题。但。正如我在评论中提到的，您必须将 geo_location 拆分为 lat 和 lng。

完成后，公式如下。这将以公里为单位计算距离。

$distance = 50; //max distance in km
$limit = 100; //the amount of selected records
$earthRadiusKm = 6371;
$earthRadiusMiles = 3959;
$postcode = $this->formatPostcode($request->postcode);
$geom = Geom::query()->where('postcode', $postcode)->first();
$lat = $geom->lat;
$lng = $geom->lng;

//assuming your Geom model db name is geoms and the 'id' is id
$postcodeDistances = \DB::table('geoms')->selectRaw("
        geoms.id,  ( $earthRadiusKm * acos( cos( radians($lat) ) * cos( radians( geoms.lat ) ) 
        * cos( radians( geoms.lng ) - radians($lng) ) + sin( radians($lat) ) *
        sin(radians(geoms.lat)) ) ) AS distance, lat, lng
    ")->havingRaw("distance < $distance")->orderBy('distance')->limit($limit)->get();

为了您的兴趣，如果您想要以英制英里为单位的结果，我在两个指标中都添加了地球半径。由于该公式确实利用了地球的半径，因此更长的距离会更准确。

结果（json）应该是这样的（2条记录结果，第一个坐标总是起点）。仅供参考，坐标在菲律宾。

all: [
   {#3627
     +"id": 1128,
     +"distance": 0.0,
     +"lat": "15.6672998",
     +"lng": "120.7349950",
   },
   {#3595
     +"id": 1535,
     +"distance": 9.564007130831,
     +"lat": "15.6732128",
     +"lng": "120.6458749",
   },
]