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云火商店'!='查询

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AVAVT · 技术社区 · 6 年前

firestore docs ,我可以表演相当于一个'!='通过组合'>'和'<'查询进行查询:

但我该怎么做呢?如果可能,请提供该示例的代码(查询结果!=30)。

2 回复 | 直到 6 年前

Renaud Tarnec 6 年前

实际上,使用如下查询将不起作用(基于您参考的文档中有关城市的示例):

var query = citiesRef.where("population", ">", 860000).where("population", "<", 860000);

我认为您引用的文档摘录意味着您必须声明两个查询(见下文),并在代码中合并这两个查询的结果。

var query1 = citiesRef.where("population", ">", 860000);
var query2 = citiesRef.where("population", "<", 860000);

或

var query1 = yourRef.where("age", ">", "30");
var query2 = yourRef.where("age", "<", "30");

下面是一个适用于城市的代码示例 doc . 依次打开这两个HTML页面。第一个将创造一些城市的记录。第二个将把两个查询的结果连接到一个数组中,并在控制台中打印出来。

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>2</title>

    <script src="https://www.gstatic.com/firebasejs/5.3.1/firebase-app.js"></script>
   <script src="https://www.gstatic.com/firebasejs/5.3.1/firebase-firestore.js"></script>
</head>

<body>
    <script>
        // Initialize Firebase
        var config = {
            apiKey: ".....",
            authDomain: ".....",
            databaseURL: ".....",
            projectId: "....."
        };

        firebase.initializeApp(config);

        var db = firebase.firestore();
        var citiesRef = db.collection('cities');

    citiesRef.doc("SF").set({
     name: "San Francisco", state: "CA", country: "USA",
     capital: false, population: 860000,
     regions: ["west_coast", "norcal"] });
    citiesRef.doc("LA").set({
     name: "Los Angeles", state: "CA", country: "USA",
     capital: false, population: 3900000,
     regions: ["west_coast", "socal"] });
    citiesRef.doc("DC").set({
     name: "Washington, D.C.", state: null, country: "USA",
     capital: true, population: 680000,
     regions: ["east_coast"] });
    citiesRef.doc("TOK").set({
     name: "Tokyo", state: null, country: "Japan",
     capital: true, population: 9000000,
     regions: ["kanto", "honshu"] });
   citiesRef.doc("BJ").set({
     name: "Beijing", state: null, country: "China",
     capital: true, population: 21500000,
     regions: ["jingjinji", "hebei"] });

    </script>

</body>

</html>

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>2</title>

    <script src="https://www.gstatic.com/firebasejs/5.3.1/firebase-app.js"></script>
   <script src="https://www.gstatic.com/firebasejs/5.3.1/firebase-firestore.js"></script>
</head>

<body>
    <script>
        // Initialize Firebase
        var config = {
            apiKey: ".....",
            authDomain: ".....",
            databaseURL: ".....",
            projectId: "....."
        };

        firebase.initializeApp(config);

        var db = firebase.firestore();
        var citiesRef = db.collection('cities');

        var query1 = citiesRef.where("population", ">", 860000);
        var query2 = citiesRef.where("population", "<", 860000);

        var fullArray = [];    

        query1.get()
            .then(function (querySnapshot) {
                console.log(querySnapshot.docs);
                (querySnapshot.docs).forEach((element, index, array) => {
                    console.log(element.data().population);
                });
                fullArray = fullArray.concat(querySnapshot.docs);
                return query2.get();
            })
            .then(function (querySnapshot) {
                console.log(querySnapshot.docs);
                (querySnapshot.docs).forEach((element, index, array) => {
                    console.log(element.data().population);
                });
                fullArray = fullArray.concat(querySnapshot.docs);
                console.log('Final resulting array:');
                fullArray.forEach((element, index, array) => {
                    console.log(element.data().population);
                });
            })
            .catch(function (error) {
                console.log("Error getting documents: ", error);
            });

    </script>
</body>
</html>

youDaily 6 年前

https://firebase.google.com/docs/firestore/query-data/queries

查询限制

用a查询!=条款。在这种情况下,应该将查询拆分为大于查询和小于查询。例如,尽管查询子句的位置(“age”,“!不支持“,”30“),您可以通过组合两个查询(一个查询与子句)获得相同的结果集其中(“age”、“<”、“30”)和一个带有子句where(“age”、“>”, 30页)。