I am a new mongodb user, this why I am asking this question. I have a document, in this document I have 3 objects under one _id.
When I am filtering { "people.age": { $in: [24] } } I am getting full this document. But I want to see only the matching object. Like for age 24, I just want to see object 2, not object 0 and 1.
Is it possible to show only the matching object? If you kindly explain me it will be helpful for me.
Use $ for projection.
Query 1
db.collection.find({
"people.age": {
$in: [
24
]
}
},
{
"people.$": 1
})
Sample Mongo Playground (Query 1)
If you just to search people by certain age, you may use the below query as well:
Query 2
db.collection.find({
"people.age": 24
},
{
"people.$": 1
})
Sample Mongo Playground (Query 2)
Note: $ will returns only the first element of the array.
You may look for aggregation query as:
$match - Filter the document by age.$project - Decorate output documents. With $filter operator to filter the document in people array.db.collection.aggregate([
{
$match: {
"people.age": 24
}
},
{
$project: {
"people": {
$filter: {
input: "$people",
cond: {
$eq: [
"$$this.age",
24
]
}
}
}
}
}
])
Sample Mongo Playground (Aggregation pipeline)
Reference
