Mongodb – How to convert null to string in aggregation?
My collection Looks like this: [ { "_id": { "$oid": "638ecf5247cf747bdd862bfb" }, "title": "This is title one" }, { "_id": { "$oid": "638ecf5247cf747bdd862bfb" }, "title": null }, { "_id": { "$oid": "638ecf5247cf747bdd862bfb" }, "title": "This is title three" } ]…