MongoDB aggregate query - How to make array of array list in to single array - mongodb

Question

I have a document like this:
this is my example data is attached below,
[
{
"_id": ObjectId("6218b836405919280c209f7e"),
"projectId": ObjectId("6218a31f405919280c209e18"),
"accountId": ObjectId("621888e852bd8836c04b8f82"),
"personalIdRoot": [
{
"_id": ObjectId("6221e7514195b43f24c9953f"),
"personalId": ObjectId("6218b48c405919280c209f6c"),
},
{
"_id": ObjectId("6221e7514195b43f24c99540"),
"personalId": ObjectId("621ef1e40bd3a220f487cd96"),
}
],
"personalIdFill": [
{
"_id": ObjectId("6221e7514195b43f24c9953d"),
"personalId": ObjectId("6218b48c405919280c209f6c"),
},
{
"_id": ObjectId("6221e7514195b43f24c9953e"),
"personalId": ObjectId("621ef1e40bd3a220f487cd96"),
}
],
"personalIdCap": [
{
"_id": ObjectId("6221e7514195b43f24c9953b"),
"personalId": ObjectId("6218b48c405919280c209f6c"),
},
{
"_id": ObjectId("6221e7514195b43f24c9953c"),
"personalId": ObjectId("621ef1e40bd3a220f487cd96"),
}
],
"aps": ObjectId("6218bc18405919280c209f8e"),
}
]
i used this example data for my aggregate query.
my aggregate query is attached below:
please find below code:
db.getCollection('funds').aggregate([
{
$match: {
accountId: ObjectId("621888e852bd8836c04b8f82"),
projectId: ObjectId("6218a31f405919280c209e18"),
aps: {
$in: [
ObjectId("6218bc18405919280c209f8e")
]
}
}
},
{
$facet: {
"results": [
{
$group: {
_id: 0,
values: { "$addToSet": "$personalIdRoot.welderId" },
values: { "$addToSet": "$personalIdFill.welderId" },
values: { "$addToSet": "$personalIdCap.welderId" }
}
},
],
}
}
])
my result:
/* 1 */
{
"results" : [
{
"_id" : 0.0,
"values" : [
[
ObjectId("6218b48c405919280c209f6c")
],
[
ObjectId("6218b2e4405919280c209f68")
],
[
ObjectId("6218b48c405919280c209f6c"),
ObjectId("621ef1e40bd3a220f487cd96")
]
]
}
]
}
But i need my result in a single query:
/* 1 */
{
"results" : [
{
"_id" : 0.0,
"values" : [
ObjectId("6218b48c405919280c209f6c"),
ObjectId("621ef1e40bd3a220f487cd96")
]
}
]
}
I have a result of array of array collections.
but i need it in a single array. like above result
Thanks in advance.

Answer 1

It sounds like what you want is:
db.collection.aggregate([
{
$match: {
accountId: ObjectId("621888e852bd8836c04b8f82"),
projectId: ObjectId("6218a31f405919280c209e18"),
aps: {
$in: [
ObjectId("6218bc18405919280c209f8e")
]
}
}
},
{
$project: {
values: {
$setUnion: [
"$personalIdCap.personalId",
"$personalIdFill.personalId",
"$personalIdRoot.personalId"
]
}
}
}
])
See how it works on the playground example