MongoDB query with multiple conditions - mongodb

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

For the second condition, you can use the $in operator in your query as:
db.emp.find({
"type" : { "$in": ["WebUser", "User"] },
"city" : { "$in": ["Pune", "Mumbai"] }
})
If you want to use in aggregation:
db.emp.aggregate([
{
"$match": {
"type" : { "$in": ["WebUser", "User"] },
"city" : { "$in": ["Pune", "Mumbai"] }
}
},
{ "$group": { "_id": null, "ids": { "$push": "$empId" } } }
])
or simply use the distinct() method to return an array of distinct empIds that match the above query as:
var employeeIds = db.emp.distinct("empId", {
"type" : { "$in": ["WebUser", "User"] },
"city" : { "$in": ["Pune", "Mumbai"] }
});

Answer 2

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})

Answer 3

You can use mongo db $or operator.
db.emp.find({ $or: [
{ "type": "WebUser", "city": "Pune" },
{ "type": "user", "city": "Mumbai"}
]})
You can pass conditions in the array.
For more reference see mongo docs

Answer 4

Display the document where in the “StudName” has value “Ajay Rathod”.
db.Student.find({name:"ajay rathod"})
{ "_id" : ObjectId("5fdd895cd2d5a20ee8cea0de"), "
Retrieve only Student Name and Grade.
db.Student.find({},{name:1,grade:1,_id:0})
{ "name" : "dhruv", "grade" : "A" }
{ "name" : "jay", "grade" : "B" }
{ "name" : "abhi", "grade" : "C" }
{ "name" : "aayush", "grade" : "A" }
{ "name" : "sukhdev", "grade" : "B" }
{ "name" : "dhruval", "grade" : "B" }
{ "name" : "ajay rathod", "grade" : "D" }