MongoDB Aggregate $unwind $match using date - what did I miss?

Question

I'm new in MongoDB and I'm trying to work with aggregations. I partially do what I'm looking for but I have a strange behavior with dates. MongoDB info Version : 2.2.0 Operating System : Windows 7 Objective Get all comments created after '2012-11-22' Let's get an example : Data ``` db.blogs.save([ { title : "X this is my second title", author : "max", posted : new Date(), pageViews : 10, tags : [ "good", "nice" ], comments : [ { "_id" : ObjectId("50ac9fdb53a900bcb4be46d9"), author : "john", text : "pretty awesome", create : ISODate("2012-12-20T00:00:00.000Z") }, { "_id" : ObjectId("50ac9fd003a900bcb4be46d9"), author : "sam", text : "this is bad", create : ISODate("2012-12-22T00:00:00.000Z") } ], other : { foo : 5 } }, { title : "X this is my title", author : "bob", posted : new Date(), pageViews : 5, tags : [ "fun", "good", "fun" ], comments : [ { "_id" : ObjectId("50ac55db53a900bcb4be46d9"), author : "matthieu", text : "bof bof", create : ISODate("2012-12-21T00:00:00.000Z") }, { "_id…

Accepted Answer

Ho my god! Stennie is right. It's November and not December...

If I put `2012-12-21T00:00:00Z` it's working... ^^

Btw, as JohnnyHK said it's maybe better to do the operation this way :

```
db.blogs.aggregate( [
    { $project : { 'comments' : 1 } },
    { $unwind: "$comments" },
    { 
       $match: { 
          'comments.create' : {
                $gt: ISODate("2012-12-21T00:00:00Z")
          }
       } 
    }
])
```

Without using `$group` but using `$project` it seems that I get what I'm looking for.

Thank you very much both for your feedbacks!

MongoDB Aggregate $unwind $match using date - what did I miss?

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