MongoDB：如何按数组字段对文档进行排序？答案

【问题标题】：MongoDB : How to sort documents by array field?MongoDB：如何按数组字段对文档进行排序？
【发布时间】：2021-07-29 10:31:33
【问题描述】：

我需要按包含布尔值的数组字段对文档进行排序。

{
    "_id" : ObjectId("610024d989c5b829e72940c5"),
    "firstname" : "Christophe",
    "lastname" : "Pichon",
    "documents" : [
        {
            "mongoId" : "610024d90053e800143b0fd3",
            "status" : "notified",
            "signable" : true,
            "signed" : false
        },
        {
            "mongoId" : "610024d90053e800143b0fd5",
            "status" : "notified",
            "signable" : true,
            "signed" : false
        },
        {
            "mongoId" : "60fea9140053e800143b0f92",
            "status" : "notified",
            "signable" : false,
            "signed" : false
        },
        {
            "mongoId" : "610024d90053e800143b0fd7",
            "status" : "notified",
            "signable" : true,
            "signed" : false
        }
    ]
},
{
    "_id" : ObjectId("610024b189c5b829e72940c4"),
    "firstname" : "Paulette",
    "lastname" : "Besnard",
    "documents" : [
        {
            "mongoId" : "610024b00053e800143b0fc4",
            "status" : "notified",
            "signable" : true,
            "signed" : true
        },
        {
            "mongoId" : "610024b10053e800143b0fc6",
            "status" : "notified",
            "signable" : true,
            "signed" : false
        },
        {
            "mongoId" : "60fea9140053e800143b0f92",
            "status" : "notified",
            "signable" : false,
            "signed" : false
        },
        {
            "mongoId" : "610024b10053e800143b0fc8",
            "status" : "notified",
            "signable" : true,
            "signed" : false
        }
    ]
},
{
    "_id" : ObjectId("60febc9e89c5b829e72940c3"),
    "firstname" : "Louis",
    "lastname" : "Herve",
    "documents" : [
        {
            "mongoId" : "60febc9e0053e800143b0fb7",
            "status" : "notified",
            "signable" : true,
            "signed" : true
        },
        {
            "mongoId" : "60febc9e0053e800143b0fb9",
            "status" : "notified",
            "signable" : true,
            "signed" : true
        },
        {
            "mongoId" : "60fea9140053e800143b0f92",
            "status" : "notified",
            "signable" : false,
            "signed" : false
        },
        {
            "mongoId" : "60febc9e0053e800143b0fbb",
            "status" : "notified",
            "signable" : true,
            "signed" : false
        }
    ]
},

排序后，我需要这个结果：

{
    "_id" : ObjectId("60febc9e89c5b829e72940c3"),
    "firstname" : "Louis",
    "lastname" : "Herve",
},

{
    "_id" : ObjectId("610024b189c5b829e72940c4"),
    "firstname" : "Paulette",
    "lastname" : "Besnard",
},

{
    "_id" : ObjectId("610024d989c5b829e72940c5"),
    "firstname" : "Christophe",
    "lastname" : "Pichon",
},

作为：

Louis 有 2/3（已签名/可签名）文件
波莱特有 1/3
克里斯托夫 0/3

所以我需要按签名对文档进行排序，并检索签署最多文档的用户。

关于如何执行此操作的想法？

感谢您的帮助

【问题讨论】：

“签署最多的文件”是指最大签署文件数或最高百分比的签署文件？即 2/6 或 1/2 哪个应该赢
到目前为止您尝试过什么？你被困在哪里了？您面临什么问题？
嗨，@sagar-dhandhukiya 正是我想要的。感谢大家的帮助

标签： arrays database mongodb sorting

【解决方案1】：

在您的收藏中尝试此查询

db.collectionName.aggregate([{
    "$project": {
        "firstname": "$firstname",
        "lastname": "$lastname",
        "signed": { // Count will be stored in "signed" field
            "$size": { // Get size of filtered documents
                "$filter": { // Filter out signed documents
                    "input": "$documents", "as": "item", "cond": { "$eq": ["$$item.signed", true] }
                }
            }
        },
        "signable": { // Count will be stored in "signable" field
            "$size": { // Get size of filtered documents
                "$filter": { // Filter out signable documents
                    "input": "$documents", "as": "item", "cond": { "$eq": ["$$item.signable", true] }
                }
            }
        }
    }
}, {
    "$sort": { // sorting users who signed the most documents
        "signed": -1,
        "signable": -1
    }
}]);

【讨论】：