MongoDB $gt/$lt operators with prices stored as strings

Question

I\'m trying to query my database for prices greater than/less than a user specified number. In my database, prices are stored like so:

{price: \"300.00\"}
         


        

Answer 1

Starting Mongo 4.0, there is a new $toDouble aggregation operator which converts from various types to double (in this case from a string):

// { price: "300.00" }
// { price: "4.2" }
 db.collection.find({ $expr: { $gt: [{ $toDouble: "$price" }, 30] } })
// { price: "300.00" }