Filter child node query on AngularFire2 firebase

Question

I have this data structure in my firebase.

  "produtos" : {
    "3" : {
      "data" : "2017-09-21",
      "fornecedor" : {
        "cnpj" : "123234534534",
        "fantasia" : "Barreirinha"
      },
      "nNF" : 3,
      "peso" : 3,
      "precoCompra" : 6,
      "vendido" : false
    },
    "123" : {
      "data" : "2017-09-14",
      "fornecedor" : {
        "cnpj" : "123234534534",
        "fantasia" : "Barreirinha"
      },
      "nNF" : 123,
      "peso" : 23000,
      "precoCompra" : 2.21,
      "vendido" : false
    }
  }

I need to get a list of values of objects that contain the CNPJ key.

I'm using Angular, AngularFire2 and TypeScript, but I can not understand.

retrieveProdutos(cnpjFornecedor: string) {
    this.produtos = this.db.list(this.paths.pathProduto, {
      query: {
        orderByChild: 'cnpj',
        equalTo: cnpjFornecedor,
        orderByKey: true,
      }
    });
  }

How do I get this list? is returning empty.

score 0 · Answer 1 · 2017-09-22T03:47:35.417

0

You can only query one field ;

query: {
  orderByChild: "vendido",
  equalTo: "false" 
}

which for example would give you all the child nodes that have their vendido child key set to false.

Also, if you want to access each child value, you could do:

this.produtos.subscribe(produtos => {

    produtos.forEach(produto => {

        console.log("produto:", produto);

        // And here you can access each produto data 

    });
});

or, depending on you access your database:

 yourRef.on("value", (snapshot) => {

       snapshot.forEach((child) => {

                var produto = child.val();

                console.log("produto nNF", produto.nNF);

        });

});

edited Sep 22 '17 at 03:47

answered Sep 22 '17 at 03:42

but I need to filter by 'cnpj'. I tried "orderByChild: 'fornecedor/cnpj'" but I could not – Rafael Silva Sep 22 '17 at 03:50
Does cnpj has a value or is it one of your parent node? If it's a parent node and you just want to filter the results using cnpj, then you could just add this to your query: query: { orderByChild: "cnpj'" } – Sep 22 '17 at 03:57
orderByKey, instead, would sort the results of your query by their ascending key values. – Sep 22 '17 at 03:59
it has a value. I have to filter the list this way: CNPJ = 123 – Rafael Silva Sep 22 '17 at 04:02
Great, then query: { orderByChild: 'CNPJ', equalTo: 123 } would work just fine! – Sep 22 '17 at 04:05
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/155053/discussion-between-alex-and-rafael-silva). – Sep 22 '17 at 04:09

score 0 · Answer 2 · answered Sep 22 '17 at 05:50

Given your JSON, you're filtering by a nested property at a known path. This is possible by specifying the path to the property in the query:

retrieveProdutos(cnpjFornecedor: string) {
    this.produtos = this.db.list(this.paths.pathProduto, {
      query: {
        orderByChild: 'fornecedor/cnpj',
        equalTo: cnpjFornecedor
      }
    });
  }

Update: on second read you say you want to return items that have a value for nNF. In this case you can filter with:

retrieveProdutos(cnpjFornecedor: string) {
    this.produtos = this.db.list(this.paths.pathProduto, {
      query: {
        orderByChild: 'nNF',
        startAt: 0
      }
    });
  }

You'll want to note that Firebase Database queries can only order/filter on a single property. In many cases it is possible to combine the values you want to filter on into a single (synthetic) property. For an example of this and other approaches, see my answer here: http://stackoverflow.com/questions/26700924/query-based-on-multiple-where-clauses-in-firebase

Excuse me. My query only filters a field. I do not need to filter nNF, I just typed it wrong. The correct is to filter only the CNPJ — Rafael Silva, Sep 22 '17 at 10:21
I tried orderByChild: 'fornecedor/cnpj', But I did not succeed. Returns an empty list. — Rafael Silva, Sep 22 '17 at 10:23
Hmmm... that should work, although there's some unknowns in your code. Can you replace `cnpjFornecedor ` with a hardcoded value `"123234534534"`? — Frank van Puffelen, Sep 22 '17 at 14:59

Filter child node query on AngularFire2 firebase

2 Answers2