Node.js MongoDB 排序
对结果进行排序
使用 sort() 方法按升序或降序对结果进行排序。
sort() 方法接受一个参数，即一个定义排序顺序的对象。
示例
按名称字母顺序对结果进行排序
var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://:27017/";
MongoClient.connect(url, function(err, db) {
if (err) throw err;
var dbo = db.db("mydb");
var mysort = { name: 1 };
dbo.collection("customers").find().sort(mysort).toArray(function(err, result) {
if (err) throw err;
console.log(result);
db.close();
});
});
运行示例 »
将上面的代码保存在一个名为 "demo_sort.js" 的文件中并运行它
运行 "demo_sort.js"
C:\Users\你的名字>node demo_sort.js
这将产生以下结果：
[
{ _id: 58fdbf5c0ef8a50b4cdd9a86, name: 'Amy', address: 'Apple st 652'},
{ _id: 58fdbf5c0ef8a50b4cdd9a8e, name: 'Ben', address: 'Park Lane 38'},
{ _id: 58fdbf5c0ef8a50b4cdd9a8a, name: 'Betty', address: 'Green Grass 1'},
{ _id: 58fdbf5c0ef8a50b4cdd9a90, name: 'Chuck', address: 'Main Road 989'},
{ _id: 58fdbf5c0ef8a50b4cdd9a87, name: 'Hannah', address: 'Mountain 21'},
{ _id: 58fdbf5c0ef8a50b4cdd9a84, name: 'John', address: 'Highway 71'},
{ _id: 58fdbf5c0ef8a50b4cdd9a88, name: 'Michael', address: 'Valley 345'},
{ _id: 58fdbf5c0ef8a50b4cdd9a85, name: 'Peter', address: 'Lowstreet 4'},
{ _id: 58fdbf5c0ef8a50b4cdd9a8b, name: 'Richard', address: 'Sky st 331'},
{ _id: 58fdbf5c0ef8a50b4cdd9a89, name: 'Sandy', address: 'Ocean blvd 2'},
{ _id: 58fdbf5c0ef8a50b4cdd9a8c, name: 'Susan', address: 'One way 98'},
{ _id: 58fdbf5c0ef8a50b4cdd9a8d, name: 'Vicky', address: 'Yellow Garden 2'},
{ _id: 58fdbf5c0ef8a50b4cdd9a91, name: 'Viola', address: 'Sideway 1633'},
{ _id: 58fdbf5c0ef8a50b4cdd9a8f, name: 'William', address: 'Central st 954'}
]
降序排序
在 sort 对象中使用值 -1 可按降序排序。
{ name: 1 } // 升序
{ name: -1 } // 降序
示例
按名称反向字母顺序对结果进行排序
var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://:27017/";
MongoClient.connect(url, function(err, db) {
if (err) throw err;
var dbo = db.db("mydb");
var mysort = { name: -1 };
dbo.collection("customers").find().sort(mysort).toArray(function(err, result) {
if (err) throw err;
console.log(result);
db.close();
});
});
运行示例 »
将上面的代码保存在一个名为 "demo_sort_desc.js" 的文件中并运行它
运行 "demo_sort_desc.js"
C:\Users\你的名字>node demo_sort_desc.js
这将产生以下结果：
[
{ _id: 58fdbf5c0ef8a50b4cdd9a8f, name: 'William', address: 'Central st 954'},
{ _id: 58fdbf5c0ef8a50b4cdd9a91, name: 'Viola', address: 'Sideway 1633'},
{ _id: 58fdbf5c0ef8a50b4cdd9a8d, name: 'Vicky', address: 'Yellow Garden 2'},
{ _id: 58fdbf5c0ef8a50b4cdd9a8c, name: 'Susan', address: 'One way 98'},
{ _id: 58fdbf5c0ef8a50b4cdd9a89, name: 'Sandy', address: 'Ocean blvd 2'},
{ _id: 58fdbf5c0ef8a50b4cdd9a8b, name: 'Richard', address: 'Sky st 331'},
{ _id: 58fdbf5c0ef8a50b4cdd9a85, name: 'Peter', address: 'Lowstreet 4'},
{ _id: 58fdbf5c0ef8a50b4cdd9a88, name: 'Michael', address: 'Valley 345'},
{ _id: 58fdbf5c0ef8a50b4cdd9a84, name: 'John', address: 'Highway 71'},
{ _id: 58fdbf5c0ef8a50b4cdd9a87, name: 'Hannah', address: 'Mountain 21'},
{ _id: 58fdbf5c0ef8a50b4cdd9a90, name: 'Chuck', address: 'Main Road 989'},
{ _id: 58fdbf5c0ef8a50b4cdd9a8a, name: 'Betty', address: 'Green Grass 1'},
{ _id: 58fdbf5c0ef8a50b4cdd9a8e, name: 'Ben', address: 'Park Lane 38'},
{ _id: 58fdbf5c0ef8a50b4cdd9a86, name: 'Amy', address: 'Apple st 652'}
]
