我下面有两个集合，我正在通过聚合和合并来创建视图表。
account table:
{
"_id": {
"$oid": "5f61b573db16185cebfeaaf9"
},
"status": "ACTIVE",
"personalInfo": {
"entityName": "John Doe",
...
},
"createdDateTime": {
"$date": "2020-09-16T06:49:23.103Z"
},
"modifiedDateTime": {
"$date": "2020-09-16T06:49:23.103Z"
}
}
account_transactions:
{
"_id": {
"$oid": "5f61b5b3db16185cebfeab0c"
},
"accountId": "5f61b573db16185cebfeaaf9",
"transactionType": "Payment",
"transactionStatus": "NEW",
"createdDate": {
"$date": "2020-09-16T06:50:27.305Z"
},
"createdBy": "sujal.shakya@joinsage.com",
"lastModifiedDate": {
"$date": "2020-09-16T10:23:06.617Z"
}
}
{
"_id": {
"$oid": "5f61b5b3db16185cebfeab0f"
},
"accountId": "5f61b573db16185cebfeaaf9",
"transactionType": "Credit",
"createdDate": {
"$date": "2020-09-16T06:50:27.305Z"
},
"createdBy": "sujal.shakya@joinsage.com",
"lastModifiedDate": {
"$date": "2020-09-16T10:23:06.617Z"
}
}
在mongodb查询下面，将创建一个视图表，其中每个帐户都有多个交易（如果存在），如果不存在交易，则向其中添加虚拟交易以及一些虚拟字段。
db.account.aggregate(
[
{
$match: {
'status': 'ACTIVE'
}
},
{$addFields: {"accountId": {"$toString": "$_id"}}},
{
$lookup: {
from: "account_transactions",
localField: "accountId",
foreignField: "accountId",
as: "transactions"
}
},
{
"$project": {
"accountType": 1,
"transactions": {
"$cond": [
{ "$eq": [ "$transactions", [] ] },
{$concatArrays: [[{"lastModifiedDate": {$arrayElemAt: ["$account.modifiedDateTime",0]}, "transactionType" : "BLANK"}]] },//adds dummy fields
{"$filter": {
"input": "$transactions",
"as": "transactions",
"cond": {
"$or": [
{
"$eq": [
"$$transactions.transactionType",
"Payment"
]
},
{
"$eq": [
"$$transactions.transactionType",
"Sale"
]
},
{
"$eq": [
"$$transactions.transactionType",
"Debit"
]
}
]
}
}
}
},
"createdBy": 1
}
},
{$merge: {into: "account_view_table", on: "_id", whenMatched: "replace", whenNotMatched: "insert"}}
])
我现在要做的是在上面为每个交易通过匹配交易类型创建的视图表中添加一个新字段。例如：如果一个帐户有多个交易，每个交易具有不同的交易类型，则检查每个交易的transactionType并在每个交易上添加新字段“ transactionTypeOrder ”：
我一直在尝试不同的方法，但是没有任何作用
{$addFields: {"transactions.transactionTypeOrder" :
{
$cond: [{$in:["$transactions.transactionType",["Payment"]]},"1",
{$cond: [ {$in:["$transactions.transactionType",["Sale"]]},"2",
{$cond: [{$in:["$transactions.transactionType",["Debit"]]},"3", "4" ]}
]}
]
}
}},
因此，如果transactionType ==“ Payment”添加transactionTypeOrder：1，如果transactionType ==“ Sales”添加transactionTypeOrder：2等。我正在寻找的输出如下：
第二种情况下，还要检查另一个字段： 在同一笔交易中，我还必须对其他字段进行另一次检查，以检查“ transactionStatus”字段是否存在，如果不存在，则将“ transactionStatusOrderAsc”字段添加为“ ####”，将“ transactionStatusOrderDsc”添加为“ ~~~”，如果存在与“ transactionStatus”相同的值，那么输出将如下所示：
所以基本上，我必须检查transactionType并添加新的Filed，同时还要检查transactionStatus和两个需求字段。
//result view table
{
"_id": {
"$oid": "5f61b573db16185cebfeaafd"
},
//...other fields.
"transactions": [{
"transactionType": "Payment",
"transactionTypeOrder": 1,
"transactionStatus": "New",
"transactionStatusOrderAsc": "New",
"transactionStatusOrderDsc": "New"
},
{
"transactionType": "Sales",
"transactionTypeOrder": 2,
"transactionStatusOrderAsc": "####", //since transactionStatus field doesn't exist here
"transactionStatusOrderDsc": "~~~~"
},
{
"transactionType": "Debit",
"transactionTypeOrder": 3,
"transactionStatus": "Old",
"transactionStatusOrderAsc": "Old",
"transactionStatusOrderDsc": "Old"
}
]
}
答案 0 :(得分：2)
您可以使用from here来应用数组的每个元素，并使用$map来检查值并添加字段。
db.account.aggregate([
{
$match: {
"status": "ACTIVE"
}
},
{
$addFields: {
"accountId": {
"$toString": "$_id"
}
}
},
{
$lookup: {
from: "account_transactions",
localField: "accountId",
foreignField: "accountId",
as: "transactions"
}
},
{
"$project": {
"accountType": 1,
"createdBy": 1,
transactions: /**adds dummy fields*/
{
"$map": {
"input": "$transactions",
"as": "transactions",
"in": {
$switch: {
branches: [
{
case: {
$eq: [
"$$transactions.transactionType",
"Payment"
]
},
then: {
transactionType: "$$transactions.transactionType",
transactionTypeOrder: 1
}
},
{
case: {
$eq: [
"$$transactions.transactionType",
"Sales"
]
},
then: {
transactionType: "$$transactions.transactionType",
transactionTypeOrder: 2
}
},
{
case: {
$eq: [
"$$transactions.transactionType",
"Debit"
]
},
then: {
transactionType: "$$transactions.transactionType",
transactionTypeOrder: 3
}
},
],
default: {
transactionType: "$$transactions.transactionType",
transactionTypeOrder: -1
}
}
}
}
}
}
},
])
如果您需要每个事务的其他字段，则必须在每种情况下添加它们。 您可以对其进行测试$switch
第一次评论编辑
如果必须包括所有交易字段，则可以使用here而不是手动创建对象。
db.account.aggregate([
{
$match: {
"status": "ACTIVE"
}
},
{
$addFields: {
"accountId": {
"$toString": "$_id"
}
}
},
{
$lookup: {
from: "account_transactions",
localField: "accountId",
foreignField: "accountId",
as: "transactions"
}
},
{
"$project": {
"accountType": 1,
"createdBy": 1,
transactions: /**adds dummy fields*/
{
"$map": {
"input": "$transactions",
"as": "transactions",
"in": {
$switch: {
branches: [
{
case: {
$eq: [
"$$transactions.transactionType",
"Payment"
]
},
then: {
$mergeObjects: [
"$$transactions",
{
transactionTypeOrder: 1
}
]
}
},
{
case: {
$eq: [
"$$transactions.transactionType",
"Sales"
]
},
then: {
$mergeObjects: [
"$$transactions",
{
transactionTypeOrder: 2
}
]
}
},
{
case: {
$eq: [
"$$transactions.transactionType",
"Debit"
]
},
then: {
$mergeObjects: [
"$$transactions",
{
transactionTypeOrder: 3
}
]
}
},
],
default: {
$mergeObjects: [
"$$transactions",
{
transactionTypeOrder: -1
}
]
}
}
}
}
}
}
},
])