How to use $elemMatch on aggregate's projection?

Question

This is my object:

{ \"_id\" : ObjectId(\"53fdcb6796cb9b9aa86f05b9\"), \"list\" : [ \"a\", \"b\" ], \"complist\" : [ { \"a\" : \"a\", \"b\" : \"b\" }, { \"a\         


        

Answer 1

Well, it happens you can use "array.field" on a find's projection block.

 db.itens.find({},{"complist.b":1,list:{$elemMatch:{$in:["a"]}}})

did what I needed.