Mongodb filter using regex on timestamp-CodePudding

I want to filter with a regex on date. I tried this:

{ createdAt: { $regex: '2021-06-25T' }}

But it doesn't work.

How can I use a regex or something to filter for those days, on a timeStamp field?

The collections looks like this:

But the original JSON shows this:

{
  "_id": {
    "$oid": "60d635cb26bec4004fb19341"
  },
  "createdAt": {
    "$date": {
      "$numberLong": "1624651211668"
    }
  },
  "__v": 0
}

CodePudding user response：

If you want to keep everything as Dates and find documents for that specific day, you could try this.

db.collection.aggregate([
  {
    "$match": {
      "$expr": {
        "$eq": [
          {
            "$dateTrunc": {
              "date": "$createdAt",
              "unit": "day"
            }
          },
          ISODate("2021-06-25T00:00:00Z")
        ]
      }
    }
  }
])

Try it on mongoplayground.net.

CodePudding user response：

You should convert the date to a string version and then apply the match. Try something like this:

db.collection.aggregate([
  {
    "$match": {
      $expr: {
        "$regexMatch": {
          "input": {
            "$toString": "$createdAt"
          },
          "regex": "2021-06-25T"
        }
      }
    }
  }
])

Playground link.