CODEWITHSUNDEEP
mongodb
Егор Лебедев
Егор Лебедев

Reputation: 1336

how to use document fields in query in mongodb

I want to choose documents where from < now and to > (now + delay), where from, to and delay is document fields. Now is my variable. something like that

{
  from: {$gte: now},
  to: {$lte: now + $delay}
}

Upvotes: 0

Views: 30

Answers (2)

OzW
OzW

Reputation: 858

If you cannot use $expr you might consider $where.

NOTE: $where has a performance cost.

Example:

db.collection.find({
    $where: function () {
        return this.to > (now + this.delay);
    }
});

this refers to the current document. You can also you obj to reference it.

Upvotes: 0

Himanshu Sharma
Himanshu Sharma

Reputation: 3010

The following query can get us the expected output:

db.collection.find({
    "from":{
        $gte: now
    },
    $expr:{
        $lte:["$to", { $sum: ["$delay", now] }]
    }
}).pretty()

var now = 2;

Data set:

{
    "_id" : ObjectId("5d7645ab14e02904fe680e12"),
    "from" : 2,
    "to" : 4,
    "delay" : 2
}
{
    "_id" : ObjectId("5d7645ab14e02904fe680e13"),
    "from" : 2,
    "to" : 10,
    "delay" : 2
}
{
    "_id" : ObjectId("5d7645ab14e02904fe680e14"),
    "from" : 6,
    "to" : 10,
    "delay" : 2
}

Output:

{
    "_id" : ObjectId("5d7645ab14e02904fe680e12"),
    "from" : 2,
    "to" : 4,
    "delay" : 2
}

Upvotes: 1

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