How can I get only objects in the sales
array matching with 2021-10-14 date ?
My aggregate currently return all objects of sales array if at least one is matching.
Dataset Documents
{
"name": "#0",
"sales": [{
"date": "2021-10-14",
"price": 3.69,
},{
"date": "2021-10-15",
"price": 2.79,
}]
},
{
"name": "#1",
"sales": [{
"date": "2021-10-14",
"price": 1.5,
}]
}
Aggregate
{
$match: {
sales: {
$elemMatch: {
date: '2021-10-14',
},
},
},
},
{
$group: {
_id: 0,
data: {
$push: '$sales',
},
},
},
{
$project: {
data: {
$reduce: {
input: '$data',
initialValue: [],
in: {
$setUnion: ['$$value', '$$this'],
},
},
},
},
}
Result
{"date": "2021-10-14","price": 3.69},
{"date": "2021-10-15","price": 2.79},
{"date": "2021-10-14","price": 1.5}
Result Expected
{"date": "2021-10-14","price": 3.69},
{"date": "2021-10-14","price": 1.5}
CodePudding user response:
You actually need to use a $replaceRoot
or $replaceWith
pipeline which takes in an expression that gives you the resulting document filtered using $arrayElemAt
(or $first
) and $filter
from the sales
array:
[
{ $match: { 'sales.date': '2021-10-14' } },
{ $replaceWith: {
$arrayElemAt: [
{
$filter: {
input: '$sales',
cond: { $eq: ['$$this.date', '2021-10-14'] }
}
},
0
]
} }
]
OR
[
{ $match: { 'sales.date': '2021-10-14' } },
{ $replaceRoot: {
newRoot: {
$arrayElemAt: [
{
$filter: {
input: '$sales',
cond: { $eq: ['$$this.date', '2021-10-14'] }
}
},
0
]
}
} }
]
CodePudding user response:
In $project
stage, you need $filter
operator with input
as $reduce
operator to filter the documents.
{
$project: {
data: {
$filter: {
input: {
$reduce: {
input: "$data",
initialValue: [],
in: {
$setUnion: [
"$$value",
"$$this"
],
}
}
},
cond: {
$eq: [
"$$this.date",
"2021-10-14"
]
}
}
}
}
}
CodePudding user response:
How about using $unwind:
.aggregate([
{$match: { sales: {$elemMatch: {date: '2021-10-14'} } }},
{$unwind: '$sales'},
{$match: {'sales.date': '2021-10-14'}},
{$project: {date: '$sales.date', price: '$sales.price', _id: 0}}
])