To fetch data between two dates in DynamoDB, you can make use of a combination of the Partition Key and Sort Key. You will need to store the date/time information as the Sort Key while the Partition Key will be used to group related items together.

Here are the steps to fetch data between two dates in DynamoDB:

1. Create a table with a Partition Key and a Sort Key.
2. Store the date/time information as the Sort Key.
3. Use the Query operation to retrieve items between two dates. The Query operation requires that you specify a Partition Key value and a range of Sort Key values. You can use the KeyConditionExpression parameter to specify the range of Sort Key values.
4. The KeyConditionExpression parameter should contain an expression that compares the Sort Key values to the start and end dates. For example, if you want to retrieve items between 2022-01-01 and 2022-01-31, your expression might look like this:

KeyConditionExpression: "sortKey BETWEEN :start_date AND :end_date",
ExpressionAttributeValues: {
    ":start_date": {"S": "2022-01-01"},
    ":end_date": {"S": "2022-01-31"}
}

This expression will retrieve all items with Sort Key values between 2022-01-01 and 2022-01-31, inclusive.

If you need to retrieve items that span multiple partitions, you can use the Scan operation instead of the Query operation. However, keep in mind that Scan is less efficient than Query and may consume a large amount of read capacity.

I hope this helps! Let me know if you have any further questions.