Query nested data from Firebase Real-time database Android

Question

I have the structure in the image below and I want to get the whole data from the node "aaa1234" querying by "id_Usuario". How can I do that query?

This is my structure

I tried:

DatabaseReference root = database.getReference().child("Eventos").child("participantes");
Query query = root.orderByChild("id_Usuario").equalTo(2);

Just to be more clear, the "aaa1234" is a custom key, so it will be different in the next node.

You're storing the user ID as a number, so shouldn't have quotes around the value in equalTo. So: .equalTo(2) — Frank van Puffelen
– Frank van Puffelen, Commented May 12, 2017 at 4:30

Frank van Puffelen · Accepted Answer · 2017-05-12 04:45:14Z

2

I see two mistakes.

The first one is a typo, which I already marked in my comment. You're storing the user ID as a number, so shouldn't have quotes around the value in equalTo. So: .equalTo(2)

The second mistake is in the way you try to query:

DatabaseReference root = database.getReference().child("Eventos").child("participantes");

This will create a reference to the non-existing child Eventos/participantes. What you want to do instead is query Eventos, but then against property participantes/id_Usuario. So

DatabaseReference root = database.getReference().child("Eventos");
Query query = root.orderByChild("participantes/id_Usuario").equalTo(2);

answered May 12, 2017 at 4:45

Frank van Puffelen

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