英文:
How to find nested documents mongodb using the official mongo driver
问题
我有这个文档，并希望对其进行过滤，以获取 Content 数组内的文档：
[
{
"ID": "61f1244daeaea5f165851fc9",
"name": "Mulandi",
"author": "Owayo",
"description": "dnjsfnvlksfnvls",
"created_at": "2022-01-26T10:37:01.558Z",
"Section": [
{
"ID": "61f557213fd9b086c3a422c5",
"Title": "Weee",
"Content": [
{
"ID": "61f5586e3fd9b086c3a422dc",
"Subsection_Title": "Idk",
"Content": "Something"
}
]
}
]
}
]
我应该如何过滤这个文档？我尝试了以下方法，但没有成功：
pipeline := []bson.M{
{"$match": bson.M{"Name": name}},
{"$unwind": "$Section"},
{"$unwind": "$Section.Content"},
{"$project": bson.M{
"Section.Title": sectiontitle,
"Section.Content.subsectionid": iuud,
}},
}
iter, err := collection.Aggregate(ctx, pipeline)
if err != nil {
return nil, err
}
var elem models.Course
for iter.Next(ctx) {
var elem models.Section
err = iter.Decode(&elem)
if err != nil {
log.Fatal(err)
}
}
请注意，我只是将代码部分翻译成了中文，其他部分保持原样。
英文:
I have this document and would like to filter it to get and document inside the Content array :
[
{
"ID": "61f1244daeaea5f165851fc9",
"name": "Mulandi",
"author": "Owayo",
"description": "dnjsfnvlksfnvls",
"created_at": "2022-01-26T10:37:01.558Z",
"Section": [
{
"ID": "61f557213fd9b086c3a422c5",
"Title": "Weee",
"Content": [
{
"ID": "61f5586e3fd9b086c3a422dc",
"Subsection_Title": "Idk",
"Content": "Something"
}
]
}
],
}
]
how should i go about so as to filter this document i tried this but it didn't work :
pipeline := []bson.M{
{"$match": bson.M{"Name": name}},
{"$unwind": "$Section"},
{"$unwind": "$Section.Content"},
{"$project": bson.M{
"Section.Title": sectiontitle,
"Section.Content.subsectionid": iuud,
}},
}
iter, err := collection.Aggregate(ctx, pipeline)
if err != nil {
return nil, err
}
var elem models.Course
for iter.Next(ctx) {
var elem models.Section
err = iter.Decode(&elem)
if err != nil {
log.Fatal(err)
}
}
答案1
得分: 2
db.collection.aggregate([
{
"$match": {
"name": "Mulandi"
}
},
{
"$unwind": "$Section"
},
{
"$unwind": "$Section.Content"
},
{
"$match": {
"Section.Content.ID": "61f5586e3fd9b086c3a422dc"
}
},
{
"$project": {
"Subsection_Title": "$Section.Content.Subsection_Title",
"Content": "$Section.Content.Content",
"_id": "$Section.Content.ID"
}
}
])
<details>
<summary>英文:</summary>
db.collection.aggregate([
{
"$match": {
"name": "Mulandi"
}
},
{
"$unwind": "$Section"
},
{
"$unwind": "$Section.Content"
},
{
"$match": {
"Section.Content.ID": "61f5586e3fd9b086c3a422dc"
}
},
{
"$project": {
"Subsection_Title": "$Section.Content.Subsection_Title",
"Content": "$Section.Content.Content",
"_id": "$Section.Content.ID"
}
}
])
[mongoplayground][1]
[1]: https://mongoplayground.net/p/gQyDOIuqtnF
</details>
# 答案2
**得分**: 0
iuud, _ := primitive.ObjectIDFromHex(subsectionid)
pipeline := []bson.M{
{"$match": bson.M{"Name": name}},
{"$unwind": "$Section"},
{"$unwind": "$Section.Content"},
{"$match": bson.M{"Section.Content.ID": iuud}},
{"$project": bson.M{
"Subsection_Title": "$Section.Content.Subsection_Title",
"Content": "$Section.Content.Content",
"_id": "$Section.Content.ID",
}},
}
iter, err := collection.Aggregate(ctx, pipeline)
if err != nil {
return nil, err
}
var results []bson.M
if err = iter.All(context.TODO(), &results); err != nil {
log.Fatal(err)
}
这段代码帮助我找到了嵌套的文档，感谢 @YuTing 的帮助。
<details>
<summary>英文:</summary>
iuud, _ := primitive.ObjectIDFromHex(subsectionid)
pipeline := []bson.M{
{"$match": bson.M{"Name": name}},
{"$unwind": "$Section"},
{"$unwind": "$Section.Content"},
{"$match": bson.M{"Section.Content.ID": iuud}},
{"$project": bson.M{
"Subsection_Title": "$Section.Content.Subsection_Title",
"Content": "$Section.Content.Content",
"_id": "$Section.Content.ID",
}},
}
iter, err := collection.Aggregate(ctx, pipeline)
if err != nil {
return nil, err
}
var results []bson.M
if err = iter.All(context.TODO(), &results); err != nil {
log.Fatal(err)
}
This helped me finding the nested documents Thanks @YuTing
</details>
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