我有以下类型的模式
Mongo游乐场
问题——我想把所有成功的交易和他们各自的用户放在列表中，并为特定的交易提供一些额外的字段，比如奖励。就像如果在10中支付金额，则奖励将是0.3倍->3.但我需要0.3，如果第一次成功付款，其他人只需要0.1。
尝试：我已经实现了部分输出，无法获得基于第一笔交易的奖励计算
输出将为-
[
{
_id: 1,
name: 'Stephen',
transactions: [
{
_id: 1,
paidAmount: 10,
reward: 3
},
{
_id: 3,
paidAmount: 20,
reward: 2
}
]
},
{
_id: 2,
user: 'Peter',
transactions: [
{
_id: 2,
paidAmount: 5,
reward: 0.15
}]
}
]
嗨，我已经找到了上述的解决方案
db.users.aggregate([
{
$match: {
_id: 1,
},
},
{
$lookup: {
from: "payments",
localField: "_id",
foreignField: "user",
as: "payments",
},
},
{
$addFields: {
transactions: {
$reduce: {
input: "$payments",
initialValue: [],
in: {
$concatArrays: [
"$$value",
{
$filter: {
input: "$$this.transactions",
cond: {
$eq: [
"$$this.status",
"succeeded"
]
},
},
},
],
},
},
},
},
},
{
$project: {
transactions: {
$map: {
input: "$transactions",
as: "t",
in: {
paidAmount: "$$t.paidAmount",
status: "$$t.status",
createdAt: "$$t.createdAt",
reward: {
$cond: {
if: {
$eq: [
{
$indexOfArray: [
"$transactions",
"$$t"
]
},
0
]
},
then: {
$multiply: [
"$$t.paidAmount",
0.3
]
},
else: {
$multiply: [
"$$t.paidAmount",
0.1
]
},
},
},
},
},
},
},
},
{
$project: {
id: {
$toString: "$_id"
},
totalAMount: {
$sum: "$transactions.paidAmount"
},
totalReward: {
$sum: "$transactions.reward"
},
transactions: "$transactions",
},
},
])
如果您找到了更好的解决方案/方法，请发表评论。
试试这个