Node.js MongoDB 排序

排序结果

使用 sort() 方法按升序或降序对结果进行排序。

sort() 方法采用 sort() 参数来定义对象。

实例

按名称的字母顺序对结果排序:

var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017/";
MongoClient.connect(url, function(err, db) {
 if (err) throw err;
  var dbo = db.db("mydb");
 <strong> var mysort = { name: 1 };
</strong> dbo.collection("customers").find()<strong>.sort(mysort)</strong>.toArray(function(err, result) {
  if (err) throw err;
  console.log(result);
  db.close();
  });
});

将上述代码保存在名为 "demo_sort.js" 的文件中，然后运行该文件:

运行 "demo_sort.js"

结果如下:

[
 { _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'}
]

降序排列

使用排序对象中的值 -1 进行降序排序。

{name: 1} //升序

{name:-1} //降序

实例

按名称的逆字母顺序对结果排序:

var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017/";
MongoClient.connect(url, function(err, db) {
 if (err) throw err;
  var dbo = db.db("mydb");
 <strong> var mysort = { name: -1 };
</strong> dbo.collection("customers").find()<strong>.sort(mysort)</strong>.toArray(function(err, result) {
  if (err) throw err;
  console.log(result);
  db.close();
  });
});

将上述代码保存在名为 "demo_sort_desc.js" 的文件中，然后运行该文件:

运行 "demo_sort_desc.js"

结果如下:

[
 { _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'}
]