retrieve multiple objects from one which is array of objects in mongodb

Question

I using mongodb to save my user data along with array. My question is how to retrieve multiple objects that matches the given value in that user array.like this:

{ 
    _id: { objid:'0000000000000' },
    userId: 'abc',
    userItems : [
        {
            itemName: 'mango',
            date: 24,
            month: 1,
            year: 2016
        },
        {
            itemName: 'apple',
            date: 24,
            month: 1,
            year: 2016
        },
        {
            itemName: 'orange',
            date: 22,
            month: 1,
            year: 2016
        },
        {
            itemName: 'vanilla',
            date: 23,
            month: 1,
            year: 2016
        }
    ]
}

and expeccted result is

{
    _id: { objid: '0000000000000' },
    userId: 'abc',
    userItems: [
        {
            itemName: 'mango',
            date: 24,
            month: 1,
            year: 2016
        },
        {
            itemName: 'apple',
            date: 24,
            month: 1,
            year: 2016
        }
    ]
}

I want all the element that matches the date,month,year from this userId userItems array please help me out from this

Answer 1

We can find result by aggregation framework.

db.user.aggregate(
   {
     $unwind : "$userItems" 
   },
   {
      $match: {
        "userItems.date" : 24, 
        "userItems.month" : 1, 
        "userItems.year" : 2016
      }
   },
   {
      $group: {
         "_id" : { "id":"$_id","userId":"$userId"},
         "userItems" : {$push:"$userItems"}
      }
   },
   {
       $project:{
          "_id": "$_id.id", 
          "userId": "$_id.userId",
          "userItems": 1 
       }
   }
)

Answer 2

db.collectioName.find(
   {
      nameOfArrayYouarelookingIn: {
         $elemMatch: {
            ArrayFieldOneName: 1,
            ArrayFieldTwoName: 'blahblah'
         }
      }
   }
)

See $elemMatch documentation for more details and examples.