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[英]filter nested array of objects at multiple level and get back the matched objects in the array
[英]Get multiple matched elements from the double nested array of objects mongodb
主集合文檔包含工作流詳細信息。 每個工作流詳細信息都有一個工作流狀態對象,並且鏈接中有一個對象數組。
當 from.nodeId = "value" 時,我需要從 links 數組中找到所有匹配的對象
{
"workflowId": "YNmwuXwQKElY",
"name": "Hello ",
"workflowState": {
"searchType": "tasks",
"links": [
{
"id": "67dca090-dd7a-4b86-8522-456ccdb891b2",
"from": {
"nodeId": "NecHqBJvxk",
"portId": "port1"
},
"to": {
"nodeId": "NecHqBJvxk",
"portId": "port2"
}
},
{
"id": "9b7a4d78-d4e6-4229-a091-24f87e3e1fa4",
"from": {
"nodeId": "PEfgrTpFOB",
"portId": "port2"
},
"to": {
"nodeId": "nUjhZhIwky",
"portId": "port1"
},
"headerValue": "Identifiers"
},
{
"id": "6e3fb202-7e29-46e0-b940-a4908ae8bb95",
"from": {
"nodeId": "NecHqBJvxk",
"portId": "port2"
},
"to": {
"nodeId": "PEfgrTpFOB",
"portId": "port1"
},
"headerValue": "Conditions",
}
],
"hovered": {},
},
"archive": true
}
我試過這個查詢
db.collection.find({
"workflowState.links": {
$elemMatch: {
"from.nodeId": "NecHqBJvxk"
}
}
},
{
"workflowState.links.$": 1
})
但它只返回數組中的第一個匹配項。
我期望這種格式的輸出。
{
"_id": ObjectId("5a934e000102030405000000"),
"workflowState": {
"links": [
{
"from": {
"nodeId": "NecHqBJvxk",
"portId": "port1"
},
"id": "67dca090-dd7a-4b86-8522-456ccdb891b2",
"to": {
"nodeId": "NecHqBJvxk",
"portId": "port2"
}
},
{
"id": "6e3fb202-7e29-46e0-b940-a4908ae8bb95",
"from": {
"nodeId": "NecHqBJvxk",
"portId": "port2"
},
"to": {
"nodeId": "PEfgrTpFOB",
"portId": "port1"
},
"headerValue": "Conditions"
}
]
}
}
如何從符合條件的數組中獲取對象的所有元素?
提前致謝
在 $unwind 階段使用聚合函數
db.collection.aggregate([
// Match possible documents
{ "$match": {
"workflowState.links.from.nodeId": "NecHqBJvxk"
}},
// Unwind each array
{ "$unwind": "$workflowState.links" },
// Filter just the matching elements
{ "$match": {
"workflowState.links.from.nodeId": "NecHqBJvxk"
}},
// Group to inner array
{ "$group": {
"_id": "$_id",
"links": { "$push": "$workflowState.links" }
}},
{
"$project":{
_id: "$_id",
"workflowState.links": "$links",
}
}
]);
要僅獲取數組中的匹配元素,請按如下方式在聚合中使用$filter :
db.test.aggregate( [
{
$project: {
"workflowState.links": {
$filter: {
input: "$workflowState.links",
as: "link",
cond: {
$or: [
{ $eq: [ "$$link.from.nodeId", "NecHqBJvxk" ] },
{ $eq: [ "$$link.to.nodeId", "NecHqBJvxk" ] }
]
}
}
}
}
}
] )
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