MongoDB $查找对象/文档数组

2024-05-17 • 问答

我的orders集合的文档架构如下：

{
"_id" : ObjectId("Id of this record"),"location_data" : {
        "type" : "main","location_id" : ObjectId("this location's id")
    },"item_details" : [
        {
            "item_id" : ObjectId("this item's id"),"qty" : 950
        },{
            "item_id" : ObjectId("this item's id"),"qty" : 200
        }
    ]
}

我将items存储在另一个集合中，该集合的模式如下：

{
    "_id": ObjectId("this record's id"),"title": "this item's title","description": "this item's description"
}

我想要的输出是：

{
"_id" : ObjectId("Id of this record"),"item_details" : [
        {
            "title": "this item's title","item_id" : ObjectId("this item's id"),{
            "title": "this item's title","qty" : 200
        }
    ]
}

在Mongodb文档中，我没有发现任何可用于对象数组的东西。任何帮助都是可观的。

谢谢

db.orders.aggregate([ {$unwind : "$item_details"},// Since the item_details is an array,unwind it first {$lookup: // run the $lookup to join with `items` collections { from: "items",localField: "item_details.item_id",foreignField: "_id",as: "item_detailsTemp" } },{ $addFields: { "item_details" : { $mergeObjects: [ { $arrayElemAt: [ "$item_detailsTemp",0 ] },"$item_details" ] } } // Replace the existing item_details with new information },{ $group : { // Since you've ran the $unwind at early stage,group it to make the item_details as an array again "_id" : "$_id","location_data" : {$first : "$location_data"},"item_details" : {$push : "$item_details"}} } ]) // Voila! Hope this helps!

MongoDB $查找对象/文档数组

k13122603 回答：MongoDB $查找对象/文档数组

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