MongoDB match based on multiple array fields

Question

Suppose I have the following documents:

{
  "_id": "ID1",
  "A": [
    {
    "a": "abc",
    "b": true
    },
    {
    "a": "abc",
    "b": false
    },
    {
    "a": "def",
    "b": true
    }
  ]
}

{
  "_id": "ID2",
  "A": [
    {
    "a": "abc",
    "b": false
    },
    {
    "a": "abc",
    "b": false
    },
    {
    "a": "def",
    "b": true
    }
  ]
}

How can I adjust my query:

db.collection.aggregate([
  {$match: {"A.a": "abc"}},
  {$project: {A: 1}}
])

So that I match only documetns where there is at least one object in A where A.a=abc AND A.b=true? In this example the outcome would be just:

{
  "_id": "ID1",
  "A": [
    {
    "a": "abc",
    "b": true
    },
    {
    "a": "abc",
    "b": false
    },
    {
    "a": "def",
    "b": true
    }
  ]
}

Ashh · Accepted Answer · 2020-04-21 12:39:33Z

1

You need to use $elemMatch

db.collection.aggregate([
  { $match: { A: { $elemMatch: { a: "abc", b: true }}},
  { $project: { A: 1 }}
])

can use find query as well

db.collection.find(
  { A: { $elemMatch: { a: "abc", b: true }},
  { A: 1 }
)

answered Apr 21, 2020 at 12:39

Ashh

46.6k16 gold badges111 silver badges137 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

MongoDB match based on multiple array fields

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related