MongoDB query with multiple conditions

Question

I have data with multiple documents :

{
 "_id" : ObjectId("57b68dbbc19c0bd86d62e486"),
 "empId" : "1"
 "type" : "WebUser",
 "city" : "Pune"
}
{
 "_id" : ObjectId("57b68dbbc19c0bd86d62e487"),
 "empId" : "2"
 "type" : "Admin",
 "city" : "Mumbai"
}
{
 "_id" : ObjectId("57b68dbbc19c0bd86d62e488"),
 "empId" : "3"
 "type" : "Admin",
 "city" : "Pune"
}
{
 "_id" : ObjectId("57b68dbbc19c0bd86d62e489"),
 "empId" : "4"
 "type" : "User",
 "city" : "Mumbai"
}

I want to get data according to my multiple conditions :

condition 1:- {"type" : "WebUser", "city" : "Pune"}

condition 2:- {"type" : "WebUser", "city" : "Pune"} & {"type" : "User", "city" : "Mumbai"}

I want below result when run condition 1 :

    {
     "_id" : ObjectId("57b68dbbc19c0bd86d62e486"),
     "empId" : "1"
     "type" : "WebUser",
     "city" : "Pune"
    }

When I run second condition :

{
  "_id" : ObjectId("57b68dbbc19c0bd86d62e486"),
  "empId" : "1"
  "type" : "WebUser",
  "city" : "Pune"
}
{
  "_id" : ObjectId("57b68dbbc19c0bd86d62e489"),
  "empId" : "4"
  "type" : "User",
  "city" : "Mumbai"
}

I want above result by one query,

Currently I am using below aggregate query,

 db.emp.aggregate([
     { $match: { '$and': [
         {"type" : "WebUser", "city" : "Pune"}, 
         {"type" : "User", "city" : "Mumbai"}
     ] } },
     { $group: { _id: 1, ids: { $push: "$empId" } } }
 ])

Above query work for first condition & fails for other. Please help me.

Answer 1

If you are looking for the AND operator

This example checks if a field exists AND is null

db.getCollection('TheCollection').find({
    $and: [
        {'the_key': { $exists: true }},
        {'the_key': null}
    ]
})

This example checks if a field has 'value1' OR 'value2'

db.getCollection('TheCollection').find({
    $or: [
        {'the_key': 'value1'},
        {`the_key': 'value2'}
    ]
})

When just checking for null, the return contains non-existing fields plus fields with value null

db.getCollection('TheCollection').find({'the_key': null})