不能在 Nodejs 中使用不同的 Mongodb [英] Cannot use Mongodb distinct in Nodejs

问题描述

当我尝试从集合中的字段(acc")中获取所有不同的值时遇到问题

I am having a problem when I am trying to get all distinct values from a field("acc") in a collection

var mongojs = require('mongojs');
var mongodb = mongojs('mongodb://localhost:27017/na');
var mongodb_data = mongodb.collection('data');


mongodb_data.distinct(
   "acc",
   (function(err, docs){
        if(err){
            return console.log(err);
        }
        if(docs){  
            console.log(docs);
        }
   })
);

当我运行代码时，它给出了下面的错误跟踪

When I run the code, it gave the error traces below

(node:45480) DeprecationWarning: sys is deprecated. Use util instead.
/.../node_modules/mongodb/lib/utils.js:98
process.nextTick(function() { throw err; });
                              ^
TypeError: cb is not a function
    at /U.../node_modules/mongojs/lib/collection.js:69:5
    at handleCallback (/.../node_modules/mongodb/lib/utils.js:95:56)
    at /.../node_modules/mongodb/lib/db.js:313:5
    at /.../node_modules/mongodb-core/lib/connection/pool.js:455:18
    at _combinedTickCallback (internal/process/next_tick.js:67:7)
    at process._tickCallback (internal/process/next_tick.js:98:9)

推荐答案

distinct 方法接受一个 query 对象作为第二个参数，试试这个:

distinct method accept a query object as the second param, try this:

mongodb_data.distinct(
   "acc",
   {}, // query object
   (function(err, docs){
        if(err){
            return console.log(err);
        }
        if(docs){  
            console.log(docs);
        }
   })
);

这篇关于不能在 Nodejs 中使用不同的 Mongodb的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！