MongoDB, find field into array

Question

I have items like these in my collection

{
user: data,
somestuff: [somedata ...], 
terminals: [ {
   label: data,
   details: [{more content}, {}, ...]
   }]
}

I would use 'find' to extract "details" field for a specific terminal 'label' I know that there is an easy way to get the "terminals" array by:

collection.find({_id: "..."}, {_id:0, terminals: 1})

Wich return

{ terminals: [ {
   label: data,
   details: [{more content}, {}, ...]
   }]
}

I tried

collection.find({ "terminals.label": data }, { _id: 0, "terminals.$.details": 1 })

As edirican has suggested And it almost work, but it return the same structure than previously except that the terminals list contain only the labeled document

The result I expect is the details list, extracted from terminals

{ details: [{more content}, {}, ...] }

Thanks for your help !

It's not clear what your looking for. Can you update your question with an example of the result you're expecting? — addiedx44
– addiedx44, Commented Jul 22, 2014 at 21:30

Ebubekir Dirican · Accepted Answer · 2014-07-22 22:36:04Z

1

Use positional ($) projection.

http://docs.mongodb.org/manual/reference/operator/projection/positional/

collection.find({ "terminals.label": 2 }, { _id: 0, "terminals.$.details": 1 })

answered Jul 22, 2014 at 22:36

Ebubekir Dirican

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