$push (update) MongoDB

Question

I am trying to update all the documents of a collection to introduce two new elements in the array of measurements (medidas) but only in documents with "sensor_id: 2". The collection, db.datos_sensores2, has documents within like:

{
    "_id" : ObjectId("609c2c2d420a73728827e87f"),
    "timestamp" : ISODate("2020-07-01T02:15:00Z"),
    "sensor_id" : 1,
    "location_id" : 1,
    "medidas" : [
        {
            "tipo_medida" : "Temperatura",
            "valor" : 14.03,
            "unidad" : "ºC"
        },
        {
            "tipo_medida" : "Humedad_relativa",
            "valor" : 84.32,
            "unidad" : "%"
        }
    ]
}

{
    "_id" : ObjectId("609c2c2d420a73728827e880"),
    "timestamp" : ISODate("2020-07-01T02:15:00Z"),
    "sensor_id" : 2,
    "location_id" : 1,
    "medidas" : [
        {
            "tipo_medida" : "Emision_CO2",
            "valor" : 1.67,
            "unidad" : "gCO2/m2"
        },
        {
            "tipo_medida" : "Consumo_electrico",
            "valor" : 0.00155,
            "unidad" : "kWh/m2"
        }
    ]
}

I wrote this:

db.datos_sensores2.update(
{"_id":0, "location_id":1, "sensor_id": 2},
{$push:{"$medidas":{$each:[
              {"precio_kWh":0.102,"unidad":"€/kWh"}, 
              {"superficie":450,"unidad":"m2"}]}}},{multi:true})

But nothing happen...

Answer 1

the first query of update has _id:0 and couldn't find doc another thing $medidas in update query don't need $ and error accoured use this update

db.collection.update({
  "location_id": 1,
  "sensor_id": 2
},
{
  $push: {
    "medidas": {
      $each: [
        {
          "precio_kWh": 0.102,
          "unidad": "€/kWh"
        },
        {
          "superficie": 450,
          "unidad": "m2"
        }
      ]
    }
  }
},
{
  multi: true
})

https://mongoplayground.net/p/jsVRQ3eDUlh