MongoDB select all where field value in a query list

Question

How to achieve below SQL in MongoShell?

Select TableA.* from TableA where TableA.FieldB in (select TableB.FieldValue from TableB)

Mongo doc gives some example of

db.inventory.find( { qty: { $in: [ 5, 15 ] } } )

I want that array be dynamically from another query. Is it possible?

Extending my question

I have a collection of bot names

bots collection

{
    "_id" : ObjectId("53266697c294991f57c36e42"),
    "name" : "teoma"
}

I have a collection of user traffic, in that traffic collection, I have a field useragent

userTraffic Collection

{
    "_id" : ObjectId("5325ee6efb91c0161cbe7b2c"),
    "hosttype" : "http",
    "useragent" : "Mediapartners-Google",
    "is_crawler" : false,
    "City" : "Mountain View",
    "State" : "CA",
    "Country" : "United States"
}

I want to select all user traffic documents where its useragent contains any name of bot collection

This is what I have come up with

var botArray = db.bots.find({},{name:1, _id:0}).toArray()

db.Sessions.find({
    useragent: {$in: botArray}
    },{ 
        ipaddress:1
        })

Here i believe it is doing equals to comparison, but I want it to do like %% comparison

Once I get the result, I want to do an update to that result set as is_crawler= true

Tried something like this, isn't helpful

db.bots.find().forEach( function(myBot) {
    db.Sessions.find({
        useragent: /myBot.name/
        },{ 
            ipaddress:1
            }) 
     });

Another way of looping through the records, but no match found.

var bots = db.bots.find( {
    $query: {}, 
    $orderby:{
        name:1}
        });
while( bots.hasNext()) {
    var bot = bots.next();
    //print(bot.name);
    var botName = bot.name.toLowerCase();
    print(botName);
     db.Sessions.find({
        useragent: /botName/,
        is_crawler:false
        },{ 
            start_date:1,
            ipaddress:1,
            useragent:1,
            City:1,
            State:1,
            Country:1,
            is_crawler:1,
            _id:0
        })
    }

Answer 1

Finally this is how I could accomplish it.

// Get a array with values for name field
var botArray = db.bots.find({},{name:1}).toArray();

// loop through another collection
        db.Sessions.find().forEach(function(sess){
            if(sess.is_crawler == false){ // check a condition
                 // loop in the above  array
                botArray.forEach(function(b){
                //check if exists in the array
                   if(String(sess.useragent).toUpperCase().indexOf(b.name.toUpperCase()) > -1){
                        db.Sessions.update({ _id : sess._id} // find by _id
                        ,{
                            is_crawler : true // set a update value
                            },
                            {
                                upsert:false // do update only
                            })
                    } 
                  });
            }
        });