I have multiple documents in a collection like this
[
{
_id: 123,
data: 1,
details: [
{
item: "a",
day: 1
},
{
item: "a",
day: 2
},
{
item: "a",
day: 3
},
{
item: "a",
day: 4
}
],
someMoreField: "xyz"
}
]
Now I want document with _id: 123 and details field should only contain day within range of 1 to 3. So the result will be like below.
{
_id: 123,
data: 1,
details: [
{
item: 'a',
day: 1,
},
{
item: 'a',
day: 2,
},
{
item: 'a',
day: 3,
},
],
someMoreField: 'xyz',
};
I tried to do this by aggregate query as:
db.collectionaggregate([
{
$match: {
_id: id,
'details.day': { $gt: 1, $lte: 3 },
},
},
{
$project: {
_id: 1,
details: {
$filter: {
input: '$details',
as: 'value',
cond: {
$and: [
{ $gt: ['$$value.date', 1] },
{ $lt: ['$$value.date', 3] },
],
},
},
},
},
},
])
But this gives me empty result. Could someone please guide me through this?
CodePudding user response：
You are very close, you just need to change the $gt to $gte and $lt to $lte.
Another minor syntax error is you're accessing $$value.date but the schema you provided does not have that field, it seems you need to change it to $$value.day, like so:
db.collection.aggregate([
{
$match: {
_id: 123,
"details.day": {
$gt: 1,
$lte: 3
}
}
},
{
$project: {
_id: 1,
details: {
$filter: {
input: "$details",
as: "value",
cond: {
$and: [
{
$gte: [
"$$value.day",
1
]
},
{
$lte: [
"$$value.day",
3
]
},
],
},
},
},
},
},
])