How can I count documents by specific date range - mongodb

Question

I have switched sql to mongodb recently and I ran into an issue.
Search schema:
new mongoose.Schema({
content: {
type: String,
required: true
},
created_at: {
type: Date,
default: Date.now
})
Some docs:
_id:5e077923f08564374cea9f55
content:"ds"
created_at:2019-12-28T15:47:47.318+00:00
_id:5e077924f08564374cea9f56
content:"ds"
created_at:2019-12-28T15:47:48.545+00:00
_id:5e07792bf08564374cea9f57
content:"d"
created_at:2019-12-28T15:47:55.585+00:00
How can I count search IN A DAY / WEEK / MONTH.
I have an idea, try to convert date to int. But I don't know how to do it.
Thank you very much.

Answer 1

You can use $year, $month to group your date field by year, month and then calculate count for this group. One sample query would look like this -
db.col.aggregate([
{
$group: {
"_id": {
"year" : {
$year : "$createdDate"
},
"month" : {
$month : "$createdDate"
}
},
"count": {
$sum: 1
}
}
}
])

Answer 2

How can I count documents by specific date range
You can specify a range of dates, start and end (and this range can include any number of days: one day, 7 days, 30 days, etc.) and get a count for that.
var start = ISODate("2019-12-25T09:00:00.000+00:00")
var end = ISODate("2019-12-30T17:00:00.000+00:00")
db.dates.aggregate( [
{
$match: {
$and: [ { created_at: { $gte: start } },
{ created_at: { $lte: end } }
]
}
},
{
$group: {
_id: null,
count: { $sum: 1 }
}
}
] )
The query can also be written as a single $group stage:
{
$group: {
_id: null,
count: {
$sum: {
$cond: [
{ $and: [
{ $gte: [ "$created_at", start ] },
{ $lte: [ "$created_at", end ] }
] },
1,
0
]
}
}
}
}