Mongo query with projection

Question

In mongo how to return all the match dict element from a list if the condition is match.

here is my data:

    {"packages": [
       {"package_name" : "abc", "installed_date" : "2016-08-03"},
       {"package_name" : "def", "installed_date" : "2016-08-04"},
       {"package_name" : "ghi", "installed_date" : "2016-08-03"},
       ]
    }

How should I query to get all the dictionary which match {"installed_date" : "2016-08-03"}

I tried:

db.resource.find({packages: {"$elemMatch": {installed_date: "2016-08-03"}}})

But this give me all the array element. I would like to get the dict element which match {installed_date: "2016-08-03"}

Thanks

Answer 1

Try mongo aggregation:

db.resource.aggregate([
  {'$match':{'packages.installed_date':'2016-08-03'}}, 
  {'$unwind':'$packages'}, 
  {'$match':{'packages.installed_date':'2016-08-03'}}, 
  {'$group':{'_id':'$_id', 'packages':{'$push':'$packages'}}}
])