Mongoose，按填充字段对查询进行排序 [英] Mongoose, sort query by populated field

问题描述

据我所知，可以使用 Mongoose (来源).

As far as I know, it's possible to sort populated docs with Mongoose (source).

我正在寻找一种按一个或多个填充字段对查询进行排序的方法.

I'm searching for a way to sort a query by one or more populated fields.

考虑这两个猫鼬模式:

var Wizard = new Schema({
    name  : { type: String }
, spells  : { [{ type: Schema.ObjectId, ref: 'Spell' }] }
});

var Spell = new Schema({
    name    : { type: String }
,   damages : { type: Number }
});

示例 JSON:

[{
    name: 'Gandalf',
    spells: [{
            name: 'Fireball',
            damages: 20
        }]
}, {
    name: 'Saruman',
    spells: [{
            name: 'Frozenball',
            damages: 10
        }]
}, {
    name: 'Radagast',
    spells: [{
            name: 'Lightball',
            damages: 15
        }]
}]

我想根据法术伤害对这些法师进行排序，使用类似的方法:

I would like to sort those wizards by their spell damages, using something like :

WizardModel
  .find({})
  .populate('spells', myfields, myconditions, { sort: [['damages', 'asc']] })
// Should return in the right order: Saruman, Radagast, Gandalf

我实际上是在查询后手工进行这些排序，并希望对其进行优化.

I'm actually doing those sorts by hands after querying and would like to optimize that.

推荐答案

你可以只明确指定 populate 方法所需的参数:

You can explicitly specify only required parameters of populate method:

WizardModel
  .find({})
  .populate({path: 'spells', options: { sort: [['damages', 'asc']] }})

看看 http://mongoosejs.com/docs/api.html#document_Document-populate这是上面链接中的一个示例.

Have a look at http://mongoosejs.com/docs/api.html#document_Document-populate Here is an example from a link above.

doc
.populate('company')
.populate({
  path: 'notes',
  match: /airline/,
  select: 'text',
  model: 'modelName'
  options: opts
}, function (err, user) {
  assert(doc._id == user._id) // the document itself is passed
})

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