CODEWITHSUNDEEP
node.jsmongodbmongoose
lostintranslation
lostintranslation

Reputation: 24583

Mongodb aggreate, cannot get sort to work on date field

Data:

{ 
  "properties" : { 
    "user" : ObjectId("51d3053627f4169a52000005"), 
    "createdOn" : ISODate("2013-07-02T18:00:03.841Z")
  }, 
  "_id" : ObjectId("51d31a87716fb81a58000003"), 
  "geometry" : { 
    "type" : "Point", 
    "coordinates" : [ 10, 10 ] 
  } 
},{ 
  "properties" : { 
    "user" : ObjectId("51d3053627f4169a52000005"), 
    "createdOn" : ISODate("2013-07-02T18:23:03.841Z")
  }, 
  "_id" : ObjectId("51d31a87716fb81a58000003"), 
  "geometry" : { 
    "type" : "Point", 
    "coordinates" : [ 20, 20 ] 
  } 
}

And I am trying the following query:

db.locations.aggregate(
  { $group: { 
    _id: "$properties.user", 
    locations: { 
      $push: {
        location: {geometry: "$geometry", properties: "$properties"} 
      } 
    }
  }}, 
  { $sort: { "properties.createdOn": 1 }}
);

No matter which direction I change the sort flag (1/-1) the order of my results does not change.

Any ideas?

Upvotes: 0

Views: 133

Answers (1)

JohnnyHK
JohnnyHK

Reputation: 312149

After the $group, your pipeline docs only contain those fields defined in the $group, so properties.createdOn doesn't exist for the $sort operation.

Move your $sort before the $group in the pipeline instead:

db.locations.aggregate(
  { $sort: { "properties.createdOn": 1 }},
  { $group: { 
    _id: "$properties.user", 
    locations: { 
      $push: {
        location: {geometry: "$geometry", properties: "$properties"} 
      } 
    }
  }}
);

Upvotes: 3

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