MongoDB get docs where month of date is equal to specific month-CodePudding

i have collection vacation that looks like something like this :

[
  {
  _id: ..
  employeeId: ...
  type: ...
  startDate:2022-09-10T00:00:00.000 00:00
  endDate: 2022-09-15T00:00:00.000 00:00
  }
  {
  _id: ..
  employeeId: ...
  type: ...
  startDate:2022-01-10T00:00:00.000 00:00
  endDate: 2022-02-15T00:00:00.000 00:00
  }
  {
  _id: ..
  employeeId: ...
  type: ...
  startDate:2022-03-10T00:00:00.000 00:00
  endDate: 2022-04-15T00:00:00.000 00:00
  }
]
...

i want to get docs only when the month in startDate is equal to specific month


const Vacation = require("../models/Vacation");

const vacations = await Vacation.find({// where month in startDate is equal to 2})

how can i perform such query ? thanks in advance

CodePudding user response：

You can write an aggregation query like this:

const vacations = await Vacation.aggregate(
 [
  {
    "$match": {
      $expr: {
        "$eq": [
          {
            "$month": {
              "$dateFromString": {
                "dateString": "$startDate",
              }
            }
          },
          3
        ]
      }
    }
  },
 ]
);

Here we, construct a date object from a string using $dateFromString operator, and then find the month value using $month. Then we perform an equality comparison, using $eq. Read more about aggregation operations on MongoDB here. See the above query working here.