Firebase - Queries

Firebase offers various ways of ordering data. In this chapter we will show simple query examples.
We will use the same data from our last chapter.

Order By Child

To order data by name, we can use the following code.

Example

var playersRef = firebase.database().ref("players/");

playersRef.orderByChild("name").on("child_added", function(data) {
   console.log(data.val().name);
});

We will see names in alphabet order.

Order By Key

We can order data by key in similar fashion.

Example

var playersRef = firebase.database().ref("players/");

playersRef.orderByKey().on("child_added", function(data) {
   console.log(data.key);
});

Order By Value

We can also order data by value. Let's add ratings collection in Firebase.
Now we can order data by value for each player.

Example

var ratingRef = firebase.database().ref("ratings/");

ratingRef.orderByValue().on("value", function(data) {
   data.forEach(function(data) {
      console.log("The " + data.key + " rating is " + data.val());
   });
});