MongoDB - How to get last month records - mongodb

Question

How can I fetch last month's records in MongoDB?
Following is the MYSQL query used to do the same:
SELECT * FROM table
WHERE YEAR(createdon) = YEAR(CURRENT_DATE - INTERVAL 1 MONTH)
AND MONTH(createdon) = MONTH(CURRENT_DATE - INTERVAL 1 MONTH)

Answer 1

Solution 1: $where operator for db.collection.find()
Supported version: Before 4.4
You can use $where which is supported with Javascript function().
db.collection.find({
$where: function() {
var currentDate = new Date();
var lastMonthDate = new Date(currentDate.setMonth(currentDate.getMonth() - 1));
return this.createdOn.getFullYear() === lastMonthDate.getFullYear()
&& this.createdOn.getMonth() === lastMonthDate.getMonth();
}
})
Note:
Wrap the function with the quotes in Mongo Playground is due to reported Github issue.
Sample Solution 1 on Mongo Playground
Solution 2: With $dateAdd for db.collection.aggregate()
Supported version: 5.0
With $dateAdd is introduced in version 5.0, you can perform the query as below:
$match:
With $match pipeline, using $expr query expression to include the aggregation operation.
$and operator to ensure both expressions are fulfilled.
Using $dateAdd operator to add month (unit) by -1 (amount) to get previous month date.
$month and $year are for getting the month and year value from date respectively.
And perform $eq operator to check both $month and $year from createdOn are matched with both $month and $year from previous month date respectively.
db.collection.aggregate([
{
$match: {
$expr: {
$and: [
{
"$eq": [
{
$month: "$createdOn"
},
{
$month: {
$dateAdd: {
startDate: new Date(),
unit: "month",
amount: -1
}
}
}
]
},
{
"$eq": [
{
$year: "$createdOn"
},
{
$year: {
$dateAdd: {
startDate: new Date(),
unit: "month",
amount: -1
}
}
}
]
}
]
}
}
}
])
Sample Solution 2 on Mongo Playground
Solution 3: With $dateFromParts for db.collection.aggregate()
Supported version: From 3.6
You may also apply with $dateFromParts which is suggested by this Jira comment.
db.collection.aggregate([
{
$match: {
$expr: {
$and: [
{
"$eq": [
{
$month: "$createdOn"
},
{
$month: {
$let: {
"vars": {
"todayDate": new Date()
},
"in": {
$dateFromParts: {
year: {
$year: "$$todayDate"
},
month: {
$subtract: [
{
$month: "$$todayDate"
},
1
]
},
day: {
$dayOfMonth: "$$todayDate"
}
}
}
}
}
}
]
},
{
"$eq": [
{
$year: "$createdOn"
},
{
$year: {
$let: {
"vars": {
"todayDate": new Date()
},
"in": {
$dateFromParts: {
year: {
$year: "$$todayDate"
},
month: {
$subtract: [
{
$month: "$$todayDate"
},
1
]
},
day: {
$dayOfMonth: "$$todayDate"
}
}
}
}
}
}
]
}
]
}
}
}
])
Sample Solution 3 on Mongo Playground

Answer 2

You can select the records between two dates using the $gte and $lte options. Example:
db.getCollection('your-collection-name').find({
{createdAt:{$gte:ISODate(“2020-03-01”),$lt:ISODate(“2021-03-31”)}}
})
more information about these operators:
$lte -> https://docs.mongodb.com/manual/reference/operator/query/lte/
$gte -> https://docs.mongodb.com/manual/reference/operator/query/gte/