Querying a Feature Layer doesn't work

[Kevin_C]

I'm following along with this tutorial for Querying a feature layer using the ArcGIS JavaScript API, but using my own layer. 

I am trying to query all features within the layer that have a value of 3 in the field called "mag". I'm supposed to get the length of the features in the query result when I console.log. This should not be 0.

But I am getting a result of 0, implying that I didn't get the query correct. What should my query statement query.where = "mag = 3"; be changed to here? 

var query = new Query();

query.where = "mag = 3";

query.outfields = ["*"];

query.returnGeometry = true;

var queryTask = new QueryTask({

url: "https://services5.arcgis.com/.../arcgis/rest/services/datalayer/FeatureServer"

});

queryTask.execute(query)

.then(function(result) {

console.log(result.features.length)

})

.otherwise(function(e) {

console.log(e);

})

Thanks!

[Kevin_C]

Solved it. Turns out I was using the url for Feature Service. Not the layer itself. Fixing the url works.