Return all fields MongoDB Aggregate

Question

I tried searching on here but couldn\'t really find what I need. I have documents like this:

{
    appletype:Granny,
    color:Green,
    datePicked:2015-01-26,
         


        

Answer 1

From your description, it sounds like you want one document for each of the types of apple in your collection and showing the document with the most recent datePicked value.

Here is an aggregate query for that:

db.collection.aggregate([
  { $sort: { "datePicked": -1 },
  { $group: { _id: "$appletype", color: { $first: "$color" }, datePicked: { $first: "$datePicked" }, dateRipe: { $first: "$dateRipe" }, numPicked: { $first: "$numPicked" } } },
  { $project: { _id: 0, color: 1, datePicked: 1, dateRipe: 1, numPicked: 1, appletype: "$_id" } }
])

But then based on the aggregate query you've written, it looks like you're trying to get this:

db.collection.find({appletype: "Granny"}).sort({datePicked: -1}).limit(1);