Mongo. Query documents with an array whose childs ALL have to match a query

问题

I am trying to write a query by using the mongo aggregation framework. What I want to achive is to select the orders where ALL shipments have been delivered more than a month ago.

currently I am able to select the orders where AT LEAST ONE shipment has been delivered more than a month ago.

Here's what I have:

db['shop.orders'].aggregate(
{
  $match: { 
    shipments: { $elemMatch: { status: "Delivered", deliveredAt: {"$lte":new Date("2018-07-28")}} }
     }
})

How do I have to alter my query to only select the orders where ALL shipments have been delivered more than a month ago?

回答1:

You can use $map to apply your condition for each shipment and then use $allElementsTrue inside $expr to check if all those elements match:

db.shop_orders.aggregate([
    {
        $match: { shipments: { $exists: true, $ne: [] } }
    },
    {
        $match: {
            $expr: {
                $allElementsTrue: {
                    $map: {
                        input: "$shipments",
                        as: "shipment",
                        in: {
                            $and: [
                                { $eq: [ "$$shipment.status", "Delivered" ] },
                                { $lte: [ "$$shipment.deliveredAt", new Date("2018-07-28") ] }
                            ]
                        }
                    }
                } 
            }
        }
    }
])

来源：https://stackoverflow.com/questions/52065224/mongo-query-documents-with-an-array-whose-childs-all-have-to-match-a-query