我在引用$cond语句中引用嵌套数组项时遇到问题。
db.getCollection('bookings').aggregate([
{
$lookup: {
from: "listings",
localField: "listingId",
foreignField: "_id",
as: "listing"
}
},
{
$match: {
$and: [
{
locationId: ObjectId("5c0f0c882fcf07fb08890c27")
},
{
$or: [
{
$and: [
{
state: "booked"
},
{
startDate: {
$lte: new Date()
}
},
{
startDate: {
$gte: ISODate("2019-12-18T07:00:00.000Z")
}
}
]
},
{
$and: [
{
listing: {
$elemMatch: {
inspectionStatus: "none"
}
}
},
{
endDate: {
$lte: new Date()
}
},
{
endDate: {
$gte: ISODate("2019-12-18T07:00:00.000Z")
}
},
{
state: {
$in: [
"active",
"returned"
]
}
}
]
},
{
$and: [
{
state: {
$ne: "cancelled"
}
},
{
$or: [
{
$and: [
{
startDate: {
$gte: ISODate("2019-12-20T07:00:00.993Z")
}
},
{
startDate: {
$lte: ISODate("2019-12-21T06:59:59.999Z")
}
}
]
},
{
$and: [
{
endDate: {
$gte: ISODate("2019-12-20T07:00:00.993Z")
}
},
{
endDate: {
$lte: ISODate("2019-12-21T06:59:59.999Z")
}
}
]
}
]
}
]
}
]
}
]
}
},
{
$addFields: {
isLate: {
$cond: [
{
$or: [
{
$and: [
{
$eq: [
"$listing.0.inspectionStatus",
"none"
]
},
{
$lte: [
"$endDate",
new Date()
]
},
{
$gte: [
"$endDate",
ISODate("2019-12-18T07:00:00.000Z")
]
},
{
$in: [
"$state",
[
"active",
"returned"
]
]
},
]
},
{
$and: [
{
$eq: [
"$state",
"booked"
]
},
{
$lte: [
"$startDate",
new Date()
]
},
{
$gte: [
"$startDate",
ISODate("2019-12-18T07:00:00.000Z")
]
}
]
}
]
},
true,
false
]
}
}
}
])
在上面，$cond语句中的以下行根本不起作用：
$eq: [
"$listing.0.inspectionStatus",
"none"
]
我的问题是-如何进行上述工作？请注意，在查询之后，listing字段中始终只有一个数组项（那里不超过一个数组项）。我尝试了$listing.$0.$inspectionStatus之类的其他变体-但似乎没有任何效果。我可以沿着研究group和filter的轨迹走下去，但是当我总是只想访问listing数组中的第一个也是唯一的项目时，我觉得这太过分了。
答案 0 :(得分：1)
请在$ cond关键字
中使用 $ in 关键字代替 $ eq 关键字db.demo1.aggregate([
{
$lookup: {
from: "demo2",
localField: "listingId",
foreignField: "_id",
as: "listing"
}
},
{
$match: {
$and: [
{
locationId: ObjectId("5c0f0c882fcf07fb08890c27")
},
{
$or: [
{
$and: [
{
state: "booked"
},
{
startDate: {
$lte: new Date()
}
},
{
startDate: {
$gte: ISODate("2019-12-18T07:00:00.000Z")
}
}
]
},
{
$and: [
{
listing: {
$elemMatch: {
inspectionStatus: "none"
}
}
},
{
endDate: {
$lte: new Date()
}
},
{
endDate: {
$gte: ISODate("2019-12-18T07:00:00.000Z")
}
},
{
state: {
$in: [
"active",
"returned"
]
}
}
]
},
{
$and: [
{
state: {
$ne: "cancelled"
}
},
{
$or: [
{
$and: [
{
startDate: {
$gte: ISODate("2019-12-20T07:00:00.993Z")
}
},
{
startDate: {
$lte: ISODate("2019-12-21T06:59:59.999Z")
}
}
]
},
{
$and: [
{
endDate: {
$gte: ISODate("2019-12-20T07:00:00.993Z")
}
},
{
endDate: {
$lte: ISODate("2019-12-21T06:59:59.999Z")
}
}
]
}
]
}
]
}
]
}
]
}
},
{
$addFields: {
isLate: {
$cond: [
{
$or: [
{
$and: [
{
$in: [
"none",
"$listing.inspectionStatus",
]
},
{
$lte: [
"$endDate",
new Date()
]
},
{
$gte: [
"$endDate",
ISODate("2019-12-18T07:00:00.000Z")
]
},
{
$in: [
"$state",
[
"active",
"returned"
]
]
},
]
},
{
$and: [
{
$eq: [
"$state",
"booked"
]
},
{
$lte: [
"$startDate",
new Date()
]
},
{
$gte: [
"$startDate",
ISODate("2019-12-18T07:00:00.000Z")
]
}
]
}
]
},
true,
false
]
}
}
}
])