[转] egg(28)--mongoose使用聚合管道

文件内容

导入数据

db.order.insert({"order_id":"1","uid":10,"trade_no":"111","all_price":100,"all_num":2}) db.order.insert({"order_id":"2","uid":7,"trade_no":"222","all_price":90,"all_num":2}) db.order.insert({"order_id":"3","uid":9,"trade_no":"333","all_price":20,"all_num":6}) db.order_item.insert({"order_id":"1","title":"商品鼠标 1","price":50,num:1}) db.order_item.insert({"order_id":"1","title":"商品键盘 2","price":50,num:1}) db.order_item.insert({"order_id":"1","title":"商品键盘 3","price":0,num:1}) db.order_item.insert({"order_id":"2","title":"牛奶","price":50,num:1}) db.order_item.insert({"order_id":"2","title":"酸奶","price":40,num:1}) db.order_item.insert({"order_id":"3","title":"矿泉水","price":2,num:5}) db.order_item.insert({"order_id":"3","title":"毛巾","price":10,num:1})

db.js

var mongoose = require('mongoose');
mongoose.connect('mongodb://eggadmin:[email protected]:27017/eggcms',{ useNewUrlParser: true },function(err){ if(err){ console.log(err) return } console.log("数据库连接成功") }) module.exports = mongoose;

order.js

var mongoose = require('./db.js');
var OrderSchema = mongoose.Schema({
    order_id:{
        type:String, }, uid:Number, trade_no:String, all_price:Number, all_num:Number, }) var OrderSchema = mongoose.model('Order',OrderSchema,'order'); module.exports = OrderSchema 

order_item.js

var mongoose = require('./db.js');
var OrderItemSchema = mongoose.Schema({
    order_id:{
        type:String, }, title:String, price:Number, num:Number, }) var OrderItemSchema = mongoose.model('OrderItem',OrderItemSchema,'order_item'); module.exports = OrderItemSchema 

关联查询

app.js

var OrderModel = require('./order.js');
OrderModel.aggregate([{
    $lookup:{
        from:"order_item", localField:"order_id", foreignField:"order_id", as:"item" } }],function(err,docs){ if(err){ console.log(err); return; } console.log(JSON.stringify(docs)) })

$project 修改文档的结构

可以用来重命名，增加或者删除文档中的字段
要求查找 order 只返回文档中 trade_no 和 all_price 字段

app.js

OrderModel.aggregate([
{
    $project:{
        trade_no:1,
        all_price:1
    }
}
], function (err, docs) {
    if (err) {
        console.log(err); return; } console.log(docs) })

$match,筛选

得到总价格>90的数据

app.js

var OrderModel = require('./order.js');
var OrderItemModel = require('./order_item.js'); OrderModel.aggregate([{ $lookup: { from: "order_item", localField: "order_id", foreignField: "order_id", as: "item" }, }, { $match: { "all_price": { $gte: 90 } } }], function (err, docs) { if (err) { console.log(err); return; } // console.log(docs) console.log(JSON.stringify(docs)) })

$group

将集合中的文档进行分组，可用于统计结果。
统计每个订单的订单数量，按照订单号分组

app.js

OrderItemModel.aggregate([{
    $group:{
        _id:"$order_id",
        total:{$sum:"$sum"} } }],function (err, docs) { if (err) { console.log(err); return; } // console.log(docs) console.log(JSON.stringify(docs)) })

$sort 排序

1为升序，-1为降序

app.js

OrderModel.aggregate([
{
    $project:{
        trade_no:1, all_price:1 } }, { $sort:{"all_price":1} } ], function (err, docs) { if (err) { console.log(err); return; } console.log(docs) })

$limit 限制

只查一条

app.js

OrderModel.aggregate([
{
    $project:{
        trade_no:1, all_price:1 } }, { $sort:{"all_price":1} }, { $limit:1 } ], function (err, docs) { if (err) { console.log(err); return; } console.log(docs) })

$skip 跳过

app.js

OrderModel.aggregate([
{
    $project:{
        trade_no:1, all_price:1 } }, { $sort:{"all_price":1} }, { $skip:1 } ], function (err, docs) { if (err) { console.log(err); return; } console.log(docs) })

根据order_item,查询order的信息

查询order_item，找出商品名称是酸奶的商品，酸奶这个商品对应的订单的订单号和订单总价格等信息

第一种方式

app.js

var OrderModel = require('./order.js');
var OrderItemModel = require('./order_item.js'); OrderItemModel.find({ "_id": "5bffa9bbd8cb3dff1d3d6658" }, function (err, docs) { var order_item = JSON.parse(JSON.stringify(docs)); var order_id = order_item[0].order_id; OrderModel.find({ "order_id": order_id }, function (err, order) { order_item.order_info = order[0]; console.log(order_item) }) })

第二种方式

app.js

var OrderItemModel = require('./order_item.js');
var mongoose = require("mongoose") OrderItemModel.aggregate([{ $lookup: { from: 'order', localField: "order_id", foreignField: "order_id", as: "order_info" } }, { $match: { "_id":mongoose.Types.ObjectId('5bffa9bbd8cb3dff1d3d6658') } }], function (err, docs) { if (err) { console.log(err); return; } console.log(JSON.stringify(docs)) })