尝试使用 MongooseJs 在 Mongodb 中按嵌套数组排序时,我遇到了一个小问题。
a) 一个产品包含任务,每个任务都有子任务。
b) 任务有顺序,每个子任务也有顺序(task.order & task.subtask.order)。
这是一个示例产品文档:
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"
}
]
}
]
我正在使用 Mongodb 聚合管道对任务及其中的子任务进行排序。这是我目前所拥有的:
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"
}
]
}
]
我真的很接近,所有的订单似乎都有效。我只需要一些帮助来将子任务放回 parent 体内。非常感谢任何帮助。
谢谢
最佳答案
您从聚合管道的一开始就犯了错误
$project: {
"tasks" : 1
}
您丢失了所有数据。所以首先你需要保留它做:
$project: {
tasks: 1,
doc: {
title: "$title",
order: "$order",
description: "$description",
status: "$status"
}
}
然后执行您的 $unwind
就像您在问题中所做的那样:
{$unwind: "$tasks"}, {$unwind: "$tasks.subTasks"}
然后进行排序。您需要使用复合键进行排序,否则按 tasks.subTasks.order
排序一旦您按 tasks.order
排序,将不会保留.所以:
{$sort: {"tasks.order": -1, "tasks.subTasks.order": 1}}
然后是困难的部分。你需要 $group
返回结果,第一步是$push
返回 subTasks
,但首先,您需要再次保留任务属性:
$project: {
doc: 1,
task_id: "$tasks._id",
tasks_doc: {
title: "$tasks.title",
description: "$tasks.description",
order: "$tasks.order",
status: "$tasks.status"
},
subTasks: "$tasks.subTasks"
}
...收集 subTasks
:
$group: {
_id: {
_id: "$_id",
task_id: "$task_id",
doc: "$doc",
task_doc: "$tasks_doc"
},
subTasks: {
$push: "$subTasks"
}
}
tasks
也一样.注意在$group
期间您还需要投影回 task_doc
属性:
$group: {
_id: {
_id: "$_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"
}
}
}
然后投影回根目录doc
属性:
$project: {
_id: "$_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。这是完整的原始聚合管道,因此您可以测试并查看是否获得了所需的结果:
[
{$match: {_id: ObjectId("554a13d4b692088a38f01f3b")}},
{$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 $unwind
在那个领域的操作will return empty result .这种情况的解决方案是最初设置 null
/空字段给一些zero
值,例如"<empty-array>"
.请注意,您必须这样做 $project
每个阵列的 ionic ,在其 $unwind
之前.
看看this answer关于如何使用 $ifNull
运算符(operator)。另请查看 $size
运算符(operator) here .
处理完这部分后,需要$group
返回结果,这可以使用 $cond
operator 来实现, 检查 "<empty-array>"
值
关于MongoDb 管道聚合排序子子文件,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/30190555/