Mongodb的aggregate应用之前已经说过了。
可以参考day06
Mongoose的aggregate函数应用
var mongoose=require('./db.js');
var OrderSchema=mongoose.Schema({
order_id:String,
uid:Number,
trade_no:String,
all_price:Number,
all_num:Number
})
var OrderModel=mongoose.model('Order',OrderSchema,'order');
OrderModel.aggregate([
{
$lookup:{
from:'order_item',
localField:"order_id",
foreignField:"order_id",
as:"item"
}
}],function(err,docs){
console.log(docs)
});/*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以及订单的总价格*/
var OrderItemModel=require('./model/order_item.js');
var OrderModel=require('./model/order.js');
var mongoose=require('mongoose');
//第一种实现方式
/*
OrderItemModel.find({"_id":"5b743da92c327f8d1b360546"},function(err,docs){
// console.log(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){
// console.log(order);
order_item[0].order_info=order[0];
console.log(order_item)
})
})
*/
//第二种方式
//mongoose中获取ObjectId mongoose.Types.ObjectId
OrderItemModel.aggregate([
{
$lookup:
{
from: "order",
localField: "order_id",
foreignField: "order_id",
as: "order_info"
}
},{
$match:{_id: mongoose.Types.ObjectId('5b743da92c327f8d1b360546')}
}
],function(err,docs){
if(err){
console.log(err)
return;
}
console.log(JSON.stringify(docs))
})