mongodb，按geoNear和date排序？ [英] mongodb, sorting by geoNear and date?

问题描述

如何在mongoDB中按邻近度和日期排序？
我试过这个但是他们只是按日期排序：

how to sort by proximity and date in mongoDB? I tried this. But they just sort by date:

   coll.find({'date':{$gte:date},'location':{$nearSphere:[lat,lng]}}).sort({'date':1}).execFind(function (err, docs) {})

我感谢帮助。

推荐答案

没有直接的方法使用 $ near 或 $ nearSphere ，并按另一个字段排序，因为这两个运算符都已经排序了 find（）。当您通过日期重新排序时，您将重新排序结果。然而，您可以做的是逐步获取 $ nearSphere 的结果，并对每组结果进行排序。例如：

There's no direct way to use $near or $nearSphere and sort by another field, because both of these operators already sort the results of doing a find(). When you sort again by 'date', you're re-sorting the results. What you can do, however, is grab results from the $nearSphere incrementally, and sort each set of results. For example:

function sortByDate(a, b) { return a.date - b.date; }

// how many results to grab at a time
var itersize = 10;
// this will hold your final, two-way sorted results
var sorted_results = new Array();
for (var i=0, last=db.coll.count(); i<last-itersize; i+=itersize) {
    var results = db.coll.find( {"date":{$gte:date},
                                 // longitude, then latitude
                                 "location":[lng, lat]} ).skip(i).limit(itersize).toArray();
    // do date sorting app-side for each group of nearSphere-sorted results
    sorted_results = sorted_results.concat( results.sort(sortByDate) );
}

您还应该了解mongodb查询中指定地理空间坐标的顺序。 MongoDB使用 geojson 规范，它的X，Y，Z顺序（即经度，纬度）。

You should also be aware of the order you specify geospatial coordinates in mongodb queries. MongoDB uses the geojson spec, which does coordinates in X, Y, Z order (i.e., longitude, latitude).

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