在我的收藏集中,我有大量的文档,每个文档包含4种类别。
group
mainCategory
subCategory
subSubCategory
我正在寻找一种通过$group
来group
的方法,在group
内应该有mainCategory
的数组,在mainCategory
中应该有是subCategory
的数组,并且在subCategory
中应该有subSubCategory
的数组。结果应仅包含类别的值/名称。
预期结果:
const result = [
{
"group": "Teknik",
"mainCategory": [
{
"name": "Gaming",
"subCategory": [
{
"name": "Playstation",
"subSubCategory": [
{"name": "Games"},
{"name": "Accessories"},
{"name": "Console"}
]
},
{
"name": "Xbox",
"subSubCategory": [
{"name": "Games"},
{"name": "Accessories"},
{"name": "Console"}
]
}
]
}, {
"name": "Audio",
"subCategory": [
{
"name": "Headphones",
"subSubCategory": [
{"name": "Wireless"},
{"name": "Non Wireless"},
]
},
{
"name": "Speakers",
"subSubCategory": [
{"name": ""},
]
}
]
},
]
}
]
我认为问题在于我需要$push
父类别中的每个类别并创建新的$groups
吗?但是,当添加更多$group
时,它只是“保存”的最后一个。其他的似乎没有被“保存”。还是我做错了什么?
基于上一个示例数据和工作代码。测试数据。
https://mongoplayground.net/p/C0-L-rGPfwy
集合中的产品结构
productName :"Horizon Zero Dawn"
group:"Teknik"
mainCategory: "Gaming"
subCategory:"Playstation"
subSubCategory: "Games"
我的聚集
const categories = await Product.aggregate([
{$match: {group: 'Teknik'}},
{
$group: {
_id: {
group: '$group',
mainCategory: '$mainCategory',
subCategory: '$subCategory',
subSubCategory: '$subSubCategory',
}
},
},
{
$group: {
_id: "$_id.group",
mainCategory: {
$push:
{
name: "$_id.mainCategory",
subCategory: {
name: "$_id.subCategory",
subSubCategory: {
name: "$_id.subSubCategory"
}
}
}
},
}
},
]);
有了这个,我为每个子类别获得1个对象,但是我希望它们在同一个对象中。
"_id": "Teknik",
"mainCategory": [
{
"name": "Gaming",
"subCategory": {
"name": "Xbox",
"subSubCategory": {
"name": "Games"
}
}
},
{
"name": "Spel & Gaming",
"subCategory": {
"name": "Xbox",
"subSubCategory": {
"name": "Accessories"
}
}
},
]
答案 0 :(得分:1)
该过程是从数组的末级准备的:
- subSubCategory ()(按以下3级字段分组)
- 子类别 (按2个以下级别的字段分组,并推至高于准备好的1级)
- mainCategory (按1级以下字段分组并推至高于2级预备水平)
- 组 (计划并显示准备好的3级)
让我们一步一步看
$match
条件db.collection.aggregate([
{ $match: { group: "Teknik" } },
$group
仅包含3个主要字段,请勿添加subSubCategory
subSubCategory
阵列 {
$group: {
_id: {
group: "$group",
mainCategory: "$mainCategory",
subCategory: "$subCategory"
},
subSubCategory: {
$push: { name: "$subSubCategory" }
}
}
},
$group
上方有重复的机会subSubCategory
,因此这将删除重复的内容,如果您不想删除,则可以跳过这一部分 {
$addFields: {
subSubCategory: { $setUnion: ["$subSubCategory", [] ] }
}
},
$group
subCategory
数组,推送我们在上一组中准备的name
和subSubCategory
数组 {
$group: {
_id: {
group: "$_id.group",
mainCategory: "$_id.mainCategory"
},
subCategory: {
$push: {
name: "$_id.subCategory",
subSubCategory: "$subSubCategory"
}
}
}
},
$group
通过主要group
字段mainCategory
数组,推送我们在上一组中准备的name
和subCategory
数组 {
$group: {
_id: "$_id.group",
mainCategory: {
$push: {
name: "$_id.mainCategory",
subCategory: "$subCategory"
}
}
}
},
$project
删除_id
并显示group
和mainCategory
字段 {
$project: {
_id: 0,
group: "$_id",
mainCategory: 1
}
}
])