如何使用express.js和mongodb获取特定用户的所有负值文档? [英] how to get all negative value document for particular user using express.js with mongodb?

问题描述

我有所有插入 mongodb 的用户数据.

<预><代码>[{"user_id": "1","name": "aaaa",价值":-10}, {"user_id": "2","name": "bbbb",价值":30}, {,"user_id": "1","name": "aaaa",价值":310}, {"user_id": "2","name": "bbbb",价值":-15}, {"user_id": "1","name": "aaaa",价值":-100}, {"user_id": "3","name": "cccc",价值":390}]

如何查询我的需求?在我的文档中，一些用户包含负值.例如 user_id = 1 包含两个负值对象我需要使用查询找出我如何修改我的代码?

User.findOne({user_id: '1'},function(err, user) {如果(错误)返回下一个(错误)；if (!user) return res.status(401).send('Unauthorized');res.json(用户)；});

解决方案

要获取多个文档，请使用 find 而不是 findOne.当您使用 find 时，您将输出作为对象数组.你可以试试下面的代码

User.find({user_id: '1' ,value : {$lt : 0}},function(err, users) {如果(错误)返回下一个(错误)；res.json(用户)；});

i have all user data which is inserted in mongodb.

[
{

    "user_id": "1",
    "name": "aaaa",
    "value": -10
  }, {

    "user_id": "2",
    "name": "bbbb",
    "value": 30

  }, {
    ,
    "user_id": "1",
    "name": "aaaa",
    "value": 310

  }, {

    "user_id": "2",
    "name": "bbbb",
    "value": -15
  }, {

    "user_id": "1",
    "name": "aaaa",
    "value": -100

  }, {

    "user_id": "3",
    "name": "cccc",
    "value": 390

  }]

how to do query for my requirment? in my document some user contaning value in negative . for example user_id = 1 contaning two negative value object i need to find out using query how can i modify my code?

User.findOne({user_id: '1'},function(err, user) { 
    if (err) return next(err);
    if (!user) return res.status(401).send('Unauthorized');
    res.json(user);
    });

解决方案

To get multiple document use find instead of findOne. When you use find you get the output as array of objects. You can try the below code

User.find({user_id: '1' ,value : {$lt : 0}},function(err, users) { 
    if (err) return next(err);
    res.json(users);
});

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