MongoDb 聚合 $match 错误:“参数必须是聚合管道运算符"； [英] MongoDb aggregation $match error : "Arguments must be aggregate pipeline operators"

问题描述

我可以使用 aggregation 获取网站的所有统计信息，但我希望为某个用户提供，例如 $where.

I can get all stats of the site with aggregation but I want to it for a certain user, like $where.

所有统计数据:

games.aggregate([{
                $group: {
                    _id: '$id',
                    game_total: { $sum: '$game_amount'}, 
                    game_total_profit: { $sum: '$game_profit'}}
                }]).exec(function ( e, d ) {

                    console.log( d )            

            })

当我尝试使用 $match 运算符时，出现错误:

When I try to use $match operator, I'm getting error :

games.aggregate([{
                $match: { '$game_user_id' : '12345789' },
                $group: {
                    _id: '$id',
                    game_total: { $sum: '$game_amount'}, 
                    game_total_profit: { $sum: '$game_profit'}}
                }]).exec(function ( e, d ) {

                    console.log( d )            

            })

Arguments must be aggregate pipeline operators

我错过了什么?

推荐答案

Pipeline stage 是数组中单独的 BSON 文档:

Pipeline stages are separate BSON documents in the array:

games.aggregate([
                { $match: { 'game_user_id' : '12345789' } },
                { $group: {
                    _id: '$id',
                    game_total: { $sum: '$game_amount'}, 
                    game_total_profit: { $sum: '$game_profit'}}
                }}
]).exec(function ( e, d ) {
    console.log( d )            
});

因此 JavaScript 中的 Array 或 [] 括号表示法意味着它期望提供一个列表".这意味着一个文档"列表，它们通常以带有 {} 大括号的 JSON 表示法指定.

So the Array or [] bracket notation in JavaScript means it expects a "list" to be provided. This means a list of "documents" which are generally specified in JSON notation with {} braces.

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