I have a collection equivalent to:
[
{
"_id": ObjectId("5a934e000102030405000000"),
"sides": {
"0": {
"dist": 100
},
"1": {
"dist": 10
}
}
},
{
"_id": ObjectId("5a934e000102030405000001"),
"sides": {
"0": {
"dist": 100
}
}
}
]
I would like to perform a query that return any documents that has for any key nested in sides has the key dist with a specific value. Something like:
db.collection.find({"sides.*.dist": 10})
Here * acts as a wildcard, any key would be valid in its place.
That would retrieve:
[
{
"_id": ObjectId("5a934e000102030405000000"),
"sides": {
"0": {
"dist": 100
},
"1": {
"dist": 10
}
}
}
]
On the other hand
db.collection.find({"sides.*.dist": 100})
Would retrive both documents.
the following song and dance won't be neccessary if sides field was an array...
db.collection.find(
{
$expr: {
$gt: [{
$size: {
$filter: {
input: { $objectToArray: "$sides" },
as: "x",
cond: { $eq: ["$$x.v.dist", 10] }
}
}
}, 0]
}
})
You could get the matching elements using this
db.collection.aggregate([
{
"$project": {
"sides_array": {//Reshape the sides
"$objectToArray": "$sides"
}
}
},
{//Denormalize to get more than one matches
"$unwind": "$sides_array"
},
{
"$match": {//Condition goes here
"sides_array.v.dist": 10
}
},
{
"$group": {//Group the data back, after unwinding
"_id": "$_id",
"sides": {
"$push": "$sides_array"
}
}
},
{
"$project": {//Reshape the data
"_id": 1,
"sides": {
"$arrayToObject": "$sides"
}
}
}
])