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MongoDb管道聚合排序子文档

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MongoDb管道聚合排序子文档,mongodb,mongoose,aggregation-framework,Mongodb,Mongoose,Aggregation Framework,在使用MongooseJs按Mongodb中的嵌套数组排序时，我遇到了一个小问题 a） 产品包含任务，每个任务都有子任务。 b） 任务有顺序，每个子任务（task.order&task.subTask.order）也有顺序 以下是产品文档示例： db.products.find({_id: ObjectId("554a13d4b692088a38f01f3b")}) 结果: { "_id" : ObjectId("554a13d4b692088a38f01f3b"), "title" : "p

在使用MongooseJs按Mongodb中的嵌套数组排序时，我遇到了一个小问题

a） 产品包含任务，每个任务都有子任务。
b） 任务有顺序，每个子任务（task.order&task.subTask.order）也有顺序

以下是产品文档示例：

db.products.find({_id: ObjectId("554a13d4b692088a38f01f3b")})
结果:

{
"_id" : ObjectId("554a13d4b692088a38f01f3b"),
"title" : "product title",
"order" : 3,
"description" : "Description here ",
"status" : "live",
"tasks" : [ 
    {
        "title" : "task 1",
        "description" : "task 1 desc",
        "order" : 10,
        "_id" : ObjectId("554a13d4b692088a38f01f3a"),
        "status" : "live",
        "subTasks" : [ 
            {
                "title" : "task 1 sub 1",
                "content" : "aaa",
                "order" : -2,
                "_id" : ObjectId("554a13d4b692088a38f01f5a"),
                "status" : "live"
            }, 
            {
                "title" : "task 1 sub 2",
                "content" : "aaa",
                "order" : 1,
                "_id" : ObjectId("554a13d4b692088a38f01f3a"),
                "status" : "live"
            }, 
            {
                "title" : "task 1 sub 4",
                "content" : "aaa",
                "order" : 8,
                "_id" : ObjectId("554a13d4b692088a38f01f4a"),
                "status" : "live"
            }, 
            {
                "title" : "task 1 sub 3 ",
                "content" : "aaa",
                "order" : 2,
                "_id" : ObjectId("5550d0a61662211332d9a973"),
                "status" : "live"
            }
        ]
    }, 
    {
        "title" : "task 2",
        "description" : "task desc 2",
        "order" : 1,
        "_id" : ObjectId("5550855f9ee2db4e3958d299"),
        "status" : "live",
        "subTasks" : [ 
            {
                "title" : "task 2 sub 1",
                "content" : "bbb",
                "order" : 1,
                "_id" : ObjectId("55508f459ee2db4e3958d29a"),
                "status" : "live"
            }
        ]
    }, 
    {
        "title" : "task 3",
        "description" : "task 3 desc",
        "order" : 2,
        "_id" : ObjectId("5551b844bb343a620f85f323"),
        "status" : "live",
        "subTasks" : [ 
            {
                "title" : "task 3 sub 2",
                "content" : "cccc",
                "order" : 0,
                "_id" : ObjectId("5551b88abb343a620f85f324"),
                "status" : "live"
            }, 
            {
                "title" : "task 3 sub 4",
                "content" : "cccc",
                "order" : 1,
                "_id" : ObjectId("5551b8f1bb343a620f85f325"),
                "status" : "hidden"
            }, 
            {
                "title" : "task 3 sub 3",
                "content" : "ccc",
                "order" : 2,
                "_id" : ObjectId("5551ba40bb343a620f85f327"),
                "status" : "hidden"
            }, 
            {
                "title" : "task 3 sub 1",
                "content" : "cccc",
                "order" : -1,
                "_id" : ObjectId("5551bcb8c31283c051d30b7c"),
                "status" : "hidden"
            }
        ]
    }
]
}

我使用Mongodb聚合管道对任务及其子任务进行排序。以下是我到目前为止的情况：

    db.products.aggregate([
    {
        $project: {
            "tasks" : 1
        }
    },
    {
        $match: {
            _id: ObjectId("554a13d4b692088a38f01f3b")
        }
    },
    {
        $unwind: "$tasks"
    },
    {
        $project: {
            "tasks": 1,
            "subTasks": 1
        }
    },
    {
        $unwind: "$tasks.subTasks"
    },
    {
        $sort: {
            "tasks.subTasks.order": 1
        }
    },
    {
        $sort: {
            "tasks.order": 1
        }
    }
])
结果:

{
"result": [
    {
        "_id": ObjectId("554a13d4b692088a38f01f3b"),
        "tasks": {
            "title": "task 2",
            "description": "task desc 2",
            "order": 1,
            "_id": ObjectId("5550855f9ee2db4e3958d299"),
            "status": "live",
            "subTasks": {
                "title": "task 2 sub 1",
                "content": "bbb",
                "order": 1,
                "_id": ObjectId("55508f459ee2db4e3958d29a"),
                "status": "live"
            }
        }
    },
    {
        "_id": ObjectId("554a13d4b692088a38f01f3b"),
        "tasks": {
            "title": "task 3",
            "description": "task 3 desc",
            "order": 2,
            "_id": ObjectId("5551b844bb343a620f85f323"),
            "status": "live",
            "subTasks": {
                "title": "task 3 sub 1",
                "content": "cccc",
                "order": -1,
                "_id": ObjectId("5551bcb8c31283c051d30b7c"),
                "status": "hidden"
            }
        }
    },
    {
        "_id": ObjectId("554a13d4b692088a38f01f3b"),
        "tasks": {
            "title": "task 3",
            "description": "task 3 desc",
            "order": 2,
            "_id": ObjectId("5551b844bb343a620f85f323"),
            "status": "live",
            "subTasks": {
                "title": "task 3 sub 2",
                "content": "cccc",
                "order": 0,
                "_id": ObjectId("5551b88abb343a620f85f324"),
                "status": "live"
            }
        }
    },
    {
        "_id": ObjectId("554a13d4b692088a38f01f3b"),
        "tasks": {
            "title": "task 3",
            "description": "task 3 desc",
            "order": 2,
            "_id": ObjectId("5551b844bb343a620f85f323"),
            "status": "live",
            "subTasks": {
                "title": "task 3 sub 4",
                "content": "cccc",
                "order": 1,
                "_id": ObjectId("5551b8f1bb343a620f85f325"),
                "status": "hidden"
            }
        }
    },
    {
        "_id": ObjectId("554a13d4b692088a38f01f3b"),
        "tasks": {
            "title": "task 3",
            "description": "task 3 desc",
            "order": 2,
            "_id": ObjectId("5551b844bb343a620f85f323"),
            "status": "live",
            "subTasks": {
                "title": "task 3 sub 3",
                "content": "ccc",
                "order": 2,
                "_id": ObjectId("5551ba40bb343a620f85f327"),
                "status": "hidden"
            }
        }
    },
    {
        "_id": ObjectId("554a13d4b692088a38f01f3b"),
        "tasks": {
            "title": "task 1",
            "description": "task 1 desc",
            "order": 10,
            "_id": ObjectId("554a13d4b692088a38f01f3a"),
            "status": "live",
            "subTasks": {
                "title": "task 1 sub 1",
                "content": "aaa",
                "order": -2,
                "_id": ObjectId("554a13d4b692088a38f01f5a"),
                "status": "live"
            }
        }
    },
    {
        "_id": ObjectId("554a13d4b692088a38f01f3b"),
        "tasks": {
            "title": "task 1",
            "description": "task 1 desc",
            "order": 10,
            "_id": ObjectId("554a13d4b692088a38f01f3a"),
            "status": "live",
            "subTasks": {
                "title": "task 1 sub 2",
                "content": "aaa",
                "order": 1,
                "_id": ObjectId("554a13d4b692088a38f01f3a"),
                "status": "live"
            }
        }
    },
    {
        "_id": ObjectId("554a13d4b692088a38f01f3b"),
        "tasks": {
            "title": "task 1",
            "description": "task 1 desc",
            "order": 10,
            "_id": ObjectId("554a13d4b692088a38f01f3a"),
            "status": "live",
            "subTasks": {
                "title": "task 1 sub 3 ",
                "content": "aaa",
                "order": 2,
                "_id": ObjectId("5550d0a61662211332d9a973"),
                "status": "live"
            }
        }
    },
    {
        "_id": ObjectId("554a13d4b692088a38f01f3b"),
        "tasks": {
            "title": "task 1",
            "description": "task 1 desc",
            "order": 10,
            "_id": ObjectId("554a13d4b692088a38f01f3a"),
            "status": "live",
            "subTasks": {
                "title": "task 1 sub 4",
                "content": "aaa",
                "order": 8,
                "_id": ObjectId("554a13d4b692088a38f01f4a"),
                "status": "live"
            }
        }
    }
],
"ok": 1
}

预期结果：

{
"_id": ObjectId("554a13d4b692088a38f01f3b"),
"title": "product title",
"order": 3,
"description": "Description here ",
"status": "live",
"tasks": [
    {
        "title": "task 2",
        "description": "task desc 2",
        "order": 1,
        "_id": ObjectId("5550855f9ee2db4e3958d299"),
        "status": "live",
        "subTasks": [
            {
                "title": "task 2 sub 1",
                "content": "bbb",
                "order": 1,
                "_id": ObjectId("55508f459ee2db4e3958d29a"),
                "status": "live"
            }
        ]
    },
    {
        "title": "task 3",
        "description": "task 3 desc",
        "order": 2,
        "_id": ObjectId("5551b844bb343a620f85f323"),
        "status": "live",
        "subTasks": [
            {
                "title": "task 3 sub 1",
                "content": "cccc",
                "order": -1,
                "_id": ObjectId("5551bcb8c31283c051d30b7c"),
                "status": "hidden"
            },
            {
                "title": "task 3 sub 2",
                "content": "cccc",
                "order": 0,
                "_id": ObjectId("5551b88abb343a620f85f324"),
                "status": "live"
            },
            {
                "title": "task 3 sub 3",
                "content": "ccc",
                "order": 2,
                "_id": ObjectId("5551ba40bb343a620f85f327"),
                "status": "hidden"
            }{
                "title": "task 3 sub 4",
                "content": "cccc",
                "order": 1,
                "_id": ObjectId("5551b8f1bb343a620f85f325"),
                "status": "hidden"
            }
        ]
    }{
        "title": "task 1",
        "description": "task 1 desc",
        "order": 10,
        "_id": ObjectId("554a13d4b692088a38f01f3a"),
        "status": "live",
        "subTasks": [
            {
                "title": "task 1 sub 1",
                "content": "aaa",
                "order": -2,
                "_id": ObjectId("554a13d4b692088a38f01f5a"),
                "status": "live"
            },
            {
                "title": "task 1 sub 2",
                "content": "aaa",
                "order": 1,
                "_id": ObjectId("554a13d4b692088a38f01f3a"),
                "status": "live"
            },
            {
                "title": "task 1 sub 3 ",
                "content": "aaa",
                "order": 2,
                "_id": ObjectId("5550d0a61662211332d9a973"),
                "status": "live"
            },
            {
                "title": "task 1 sub 4",
                "content": "aaa",
                "order": 8,
                "_id": ObjectId("554a13d4b692088a38f01f4a"),
                "status": "live"
            }
        ]
    }
]

[
 {$match: {_id: ObjectId("554a13d4b692088a38f01f3b")}}, 
 {$project: {tasks: 1, doc: {title: "$title", order: "$order", description: "$description", status: "$status"}}}, 
 {$unwind: "$tasks"}, 
 {$unwind: "$tasks.subTasks"}, 
 {$sort: {"tasks.order": -1, "tasks.subTasks.order": 1}}, 
 {$project: {doc: 1, task_id: "$tasks._id", tasks_doc: {title: "$tasks.title", description: "$tasks.description", order: "$tasks.order", status: "$tasks.status"}, subTasks: "$tasks.subTasks"}}, 
 {$group: {_id: {_id: "$_id", task_id: "$task_id", doc: "$doc", task_doc: "$tasks_doc"}, subTasks: {$push: "$subTasks"}}}, 
 {$group: {_id: {_id: "$_id._id", doc: "$_id.doc"}, tasks: {$push: {_id: "$_id.task_id", title: "$_id.task_doc.title", description: "$_id.task_doc.description", order: "$_id.task_doc.order", status: "$_id.task_doc.status", subTasks: "$subTasks"}}}}, 
 {$project: {_id: "$_id._id", title: "$_id.doc.title", description: "$_id.doc.description", order: "$_id.doc.order", status: "$_id.doc.status", tasks: 1}}
]
我真的很接近，所有的订单似乎都正常。我只是需要一些帮助来把子任务放回父任务中。非常感谢您的帮助

谢谢

您从聚合管道的一开始就犯了一个错误

$project: {
            "tasks" : 1
        }
这样会丢失所有数据。因此，首先您需要进行以下操作：

$project: {
             tasks: 1,
             doc: {
                     title: "$title", 
                     order: "$order", 
                     description: "$description", 
                     status: "$status"
                  }
          }
然后按照您在问题中所做的操作执行
$unwind
s：

{$unwind: "$tasks"}, {$unwind: "$tasks.subTasks"}
然后进行排序。您需要使用复合键进行排序，否则按
tasks.subTasks.order进行排序将不会在按
tasks.order进行排序时立即生效。因此：


{$sort: {"tasks.order": -1, "tasks.subTasks.order": 1}}


然后是最难的部分。您需要
$group
返回结果，第一步是
$push
返回
子任务
，但首先，您还需要保留任务属性：


$project: {
             doc: 1, 
             task_id: "$tasks._id", 
             tasks_doc: {
                           title: "$tasks.title", 
                           description: "$tasks.description", 
                           order: "$tasks.order", 
                           status: "$tasks.status"
                        }, 
             subTasks: "$tasks.subTasks"
          }



$group: {
           _id: {
                   _id: "$_id._id", 
                   doc: "$_id.doc"
                }, 
           tasks: {
                     $push: {
                               _id: "$_id.task_id", 
                               title: "$_id.task_doc.title", 
                               description: "$_id.task_doc.description",
                               order: "$_id.task_doc.order", 
                               status: "$_id.task_doc.status" 
                               subTasks: "$subTasks"
                            }
                  }
        }



$project: {
             _id: "$_id._id", 
             title: "$_id.doc.title", 
             description: "$_id.doc.description", 
             order: "$_id.doc.order", 
             status: "$_id.doc.status", 
             tasks: 1
          }


…收集
子任务
：


$group: {
           _id: {
                   _id: "$_id", 
                   task_id: "$task_id", 
                   doc: "$doc", 
                   task_doc: "$tasks_doc"
                }, 
           subTasks: {
                        $push: "$subTasks"
                     }
        }


对于
任务
也是如此。请注意，在
$group
ing过程中，您还需要投影回
任务\u doc
属性：


$project: {
             doc: 1, 
             task_id: "$tasks._id", 
             tasks_doc: {
                           title: "$tasks.title", 
                           description: "$tasks.description", 
                           order: "$tasks.order", 
                           status: "$tasks.status"
                        }, 
             subTasks: "$tasks.subTasks"
          }



$group: {
           _id: {
                   _id: "$_id._id", 
                   doc: "$_id.doc"
                }, 
           tasks: {
                     $push: {
                               _id: "$_id.task_id", 
                               title: "$_id.task_doc.title", 
                               description: "$_id.task_doc.description",
                               order: "$_id.task_doc.order", 
                               status: "$_id.task_doc.status" 
                               subTasks: "$subTasks"
                            }
                  }
        }



$project: {
             _id: "$_id._id", 
             title: "$_id.doc.title", 
             description: "$_id.doc.description", 
             order: "$_id.doc.order", 
             status: "$_id.doc.status", 
             tasks: 1
          }


然后投影回根
doc
属性：


$project: {
             doc: 1, 
             task_id: "$tasks._id", 
             tasks_doc: {
                           title: "$tasks.title", 
                           description: "$tasks.description", 
                           order: "$tasks.order", 
                           status: "$tasks.status"
                        }, 
             subTasks: "$tasks.subTasks"
          }



$group: {
           _id: {
                   _id: "$_id._id", 
                   doc: "$_id.doc"
                }, 
           tasks: {
                     $push: {
                               _id: "$_id.task_id", 
                               title: "$_id.task_doc.title", 
                               description: "$_id.task_doc.description",
                               order: "$_id.task_doc.order", 
                               status: "$_id.task_doc.status" 
                               subTasks: "$subTasks"
                            }
                  }
        }



$project: {
             _id: "$_id._id", 
             title: "$_id.doc.title", 
             description: "$_id.doc.description", 
             order: "$_id.doc.order", 
             status: "$_id.doc.status", 
             tasks: 1
          }


基本上就是这样。以下是完整的原始聚合管道，因此您可以测试并查看是否获得所需的结果：


{
"_id": ObjectId("554a13d4b692088a38f01f3b"),
"title": "product title",
"order": 3,
"description": "Description here ",
"status": "live",
"tasks": [
    {
        "title": "task 2",
        "description": "task desc 2",
        "order": 1,
        "_id": ObjectId("5550855f9ee2db4e3958d299"),
        "status": "live",
        "subTasks": [
            {
                "title": "task 2 sub 1",
                "content": "bbb",
                "order": 1,
                "_id": ObjectId("55508f459ee2db4e3958d29a"),
                "status": "live"
            }
        ]
    },
    {
        "title": "task 3",
        "description": "task 3 desc",
        "order": 2,
        "_id": ObjectId("5551b844bb343a620f85f323"),
        "status": "live",
        "subTasks": [
            {
                "title": "task 3 sub 1",
                "content": "cccc",
                "order": -1,
                "_id": ObjectId("5551bcb8c31283c051d30b7c"),
                "status": "hidden"
            },
            {
                "title": "task 3 sub 2",
                "content": "cccc",
                "order": 0,
                "_id": ObjectId("5551b88abb343a620f85f324"),
                "status": "live"
            },
            {
                "title": "task 3 sub 3",
                "content": "ccc",
                "order": 2,
                "_id": ObjectId("5551ba40bb343a620f85f327"),
                "status": "hidden"
            }{
                "title": "task 3 sub 4",
                "content": "cccc",
                "order": 1,
                "_id": ObjectId("5551b8f1bb343a620f85f325"),
                "status": "hidden"
            }
        ]
    }{
        "title": "task 1",
        "description": "task 1 desc",
        "order": 10,
        "_id": ObjectId("554a13d4b692088a38f01f3a"),
        "status": "live",
        "subTasks": [
            {
                "title": "task 1 sub 1",
                "content": "aaa",
                "order": -2,
                "_id": ObjectId("554a13d4b692088a38f01f5a"),
                "status": "live"
            },
            {
                "title": "task 1 sub 2",
                "content": "aaa",
                "order": 1,
                "_id": ObjectId("554a13d4b692088a38f01f3a"),
                "status": "live"
            },
            {
                "title": "task 1 sub 3 ",
                "content": "aaa",
                "order": 2,
                "_id": ObjectId("5550d0a61662211332d9a973"),
                "status": "live"
            },
            {
                "title": "task 1 sub 4",
                "content": "aaa",
                "order": 8,
                "_id": ObjectId("554a13d4b692088a38f01f4a"),
                "status": "live"
            }
        ]
    }
]



[
 {$match: {_id: ObjectId("554a13d4b692088a38f01f3b")}}, 
 {$project: {tasks: 1, doc: {title: "$title", order: "$order", description: "$description", status: "$status"}}}, 
 {$unwind: "$tasks"}, 
 {$unwind: "$tasks.subTasks"}, 
 {$sort: {"tasks.order": -1, "tasks.subTasks.order": 1}}, 
 {$project: {doc: 1, task_id: "$tasks._id", tasks_doc: {title: "$tasks.title", description: "$tasks.description", order: "$tasks.order", status: "$tasks.status"}, subTasks: "$tasks.subTasks"}}, 
 {$group: {_id: {_id: "$_id", task_id: "$task_id", doc: "$doc", task_doc: "$tasks_doc"}, subTasks: {$push: "$subTasks"}}}, 
 {$group: {_id: {_id: "$_id._id", doc: "$_id.doc"}, tasks: {$push: {_id: "$_id.task_id", title: "$_id.task_doc.title", description: "$_id.task_doc.description", order: "$_id.task_doc.order", status: "$_id.task_doc.status", subTasks: "$subTasks"}}}}, 
 {$project: {_id: "$_id._id", title: "$_id.doc.title", description: "$_id.doc.description", order: "$_id.doc.order", status: "$_id.doc.status", tasks: 1}}
]


更新

如果数组字段为空或不存在（为
null
），则对该字段执行
$unwind
操作。这种情况的解决方案是首先将
null
/空字段设置为一些
零
值，例如
“”
。请注意，在每个数组的
$unwind
之前，必须对其执行
$project
操作

了解如何使用
$ifNull
运算符。还可以查看
$size
操作符


处理完此部分后，您需要
$group
返回结果，这可以通过使用来实现，以对照
“
值”
聚合的预期/预期输出是什么？您好，向问题添加了预期结果。Thx虽然这是一个极好的答案（+1），但我想补充几点。第一个错误不是在管道中，而是在建模中。在OPs数据模型中很好地说明了嵌入的过度使用可能会导致产品达到BSON文档的16MB大小限制，除了频繁和昂贵的文档迁移是非常可能的（如果不确定的话）。感谢您指出这一点。在保证初始文档小于16MB的情况下，我假设聚合管道的所有中间文档也将符合大小限制，因为我们不添加任何数据，而且我们拆分了初始文档。所以我认为大小限制没有问题，或者我遗漏了什么？或者你指的是初始数据模型？我指的是初始数据模型；）我有一个产品集合和一个任务集合，用于引用父对象，还有一个字段引用相应的产品。