mongodb match all conditions with a single array element - mongodb

Question

I have an array of tests like this,
{
"tests" : [
{
"testId" : "1",
"details" : {
"status" : "Completed"
}
},
{
"testId" : "2",
"details" : {
"status" : "InProgress"
}
},
{
"testId" : "3",
"details" : {
"status" : "Completed"
}
},
]
}
I want to search for complete tests with id as 1 or 2.
So I wrote a match query like this
{
$match : { $and : [ { "tests.testId" : { $in : [1, 2] } }
,{ "tests.details.status" : "Completed" }
]
}
}
The problem with this query is it fetches all documents with Ids as 1 or 2 even though the status is not Completed. For example the above query fetches these two documents
{
"testId" : "1",
"details" : {
"status" : "Completed"
}
},
{
"testId" : "2",
"details" : {
"status" : "InProgress"
}
},
What I need is to the query to search for a parituclat array element for both the condition.
I also tried with $elemMatch. It still doesn't work. Any help is much appreciated.

Answer 1

We can use aggregate pipeline with $filter to return the matched array elements only
try this
db.collection.aggregate([
{
$match: { // to filter the documents
$and: [
{
"tests.testId": { $in: ["1", "2"] }
},
{
"tests.details.status": "Completed"
}
]
}
},
{
$project: { // then use this $project stage to use the $filter operator in it
tests: {
$filter: { // this is to filter the tests array
input: "$tests",
as: "test",
cond: {
$and: [
{
$in: [
"$$test.testId", ["1", "2"]
]
},
{
$eq: [
"$$test.details.status",
"Completed"
]
}
]
}
}
}
}
}
])
you can test it here Mongo Playground
hope it helps
Note, If testId is of type ObjectId, then you have to use ObjectIds not strings in the aggregate pipeline