我想根據 importkeyid 和 MissingPersonIds.PhotoId 陣列欄位過濾檔案。MissingPersonIds.PhotoId 上的過濾器應該像 'sql - like ' 運算子一樣作業。
架構：
[{
"_id": {
"$oid": "61ada7da9a30fd8471869bbc"
},
"ImportKeyId": 5843,
"Name" : "AV"
"MissingPersonIds": [
{
"PhotoId": "2 - Copy.jpg",
"Description": "Account ID not found"
},
{
"PhotoId": "2 - Copy - Copy.jpg",
"Description": "Account ID not found"
},
{
"PhotoId": "2 - Copy - Copy (2).jpg",
"Description": "Account ID not found"
},
{
"PhotoId": "202020 - Copy (2).jpg",
"Description": "Account ID not found"
},
{
"PhotoId": "202020 - Copy - Copy.jpg",
"Description": "Account ID not found"
},
{
"PhotoId": "202020 - Copy - Copy (2).jpg",
"Description": "Account ID not found"
}
]
},
{
"_id": {
"$oid": "619cd7d2181999c9a4da790a"
},
"ImportKeyId": 5753,
"Name" : 'av1'
"MissingPersonIds": [
{
"PhotoId": "94578.jpg",
"Description": "Photo id is not found"
},
{
"PhotoId": "371426759.jpg",
"Description": "Photo id is not found"
}
]
}
.
.
.
]
基于以下條件：
篩選： { "ImportKeyId" : 5843 }
投影： { MissingPersonIds : { $slice:[0,5] }, "MissingPersonIds": { $elemMatch: { PhotoId : { $regex: /202020 /i } } } }
我期待低于輸出但 $elemMatch 只回傳一個匹配的記錄
[{
"_id": {
"$oid": "61ada7da9a30fd8471869bbc"
},
"ImportKeyId": 5843,
"Name" : "AV"
"MissingPersonIds": [
{
"PhotoId": "202020 - Copy (2).jpg",
"Description": "Account ID not found"
},
{
"PhotoId": "202020 - Copy - Copy.jpg",
"Description": "Account ID not found"
}
]
}]
我應該用什么來代替$elemMatch？
uj5u.com熱心網友回復：
也許像這樣
db.collection.aggregate([
{
"$match": {
"ImportKeyId": 5843
}
},
{
"$project": {
"_id": 1,
"ImportKeyId": 1,
MissingPersonIds: {
$filter: {
input: "$MissingPersonIds",
as: "item",
cond: {
$gt: [
{
$indexOfCP: [
{
$toLower: "$$item.PhotoId"
},
"202020 "
]
},
-1
]
}
}
}
}
}
])
輸出：
[
{
"_id": ObjectId("61ada7da9a30fd8471869bbc")
"ImportKeyId": 5843,
"MissingPersonIds": [
{
"Description": "Account ID not found",
"PhotoId": "202020 - Copy (2).jpg"
},
{
"Description": "Account ID not found",
"PhotoId": "202020 - Copy - Copy.jpg"
},
{
"Description": "Account ID not found",
"PhotoId": "202020 - Copy - Copy (2).jpg"
}
],
}
]
解釋：
- 在匹配階段，您僅過濾具有 ImportKeyId 的檔案：5843
- 在專案階段，您會調整 _id 和 ImportKeyId ，并添加新欄位 MissingPersonIds ，該欄位將過濾僅包含字串的陣列中的元素，例如在 SQL 中包含“ 2020 %”
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