Sorting data in DynamoDB is different from traditional SQL databases. Since DynamoDB is a NoSQL key-value and document database, sorting is only possible when certain conditions are met, primarily involving the sort key and how your query is structured.

In this guide, you'll learn:

• How sorting works in DynamoDB

• How to use Python and Boto3 to retrieve sorted results

• How to simulate sorting using additional logic

Table of Contents

1. How Sorting Works in DynamoDB

2. Prerequisites

3. Creating a Table with Sort Key

4. Sorting Using query() with Sort Key

5. Sorting Order: Ascending vs Descending

6. Sorting with Filter Expressions (Limitations)

7. Sorting Without Sort Keys (Client-Side Sort)

8. Full Example

9. Tips and Best Practices

10. Common Pitfalls

11. Conclusion

1. How Sorting Works in DynamoDB

In DynamoDB, you cannot sort data arbitrarily like in SQL using ORDER BY. Sorting is only available when:

• You use a sort key (also known as range key)

• You use the query() method, not scan()

• You define the sort direction using the ScanIndexForward parameter

⚙️ 2. Prerequisites

• Python 3.7+

• AWS account

• DynamoDB table with partition and sort key (e.g., user_id and timestamp)

• AWS credentials configured via aws configure

3. Creating a Table with Sort Key

Make sure your table includes a sort key. Example schema:

• Table name: UserLogs

• Partition key: user_id (String)

• Sort key: timestamp (String or Number)

You can create this manually in the AWS Console or programmatically via Boto3.

4. Sorting Using query() with Sort Key

import boto3
from boto3.dynamodb.conditions import Key

dynamodb = boto3.resource('dynamodb', region_name='us-east-1')
table = dynamodb.Table('UserLogs')

# Query and sort results in ascending order
response = table.query(
    KeyConditionExpression=Key('user_id').eq('123'),
    ScanIndexForward=True  # Ascending (oldest to newest)
)

for item in response['Items']:
    print(item)

Descending Order (Latest first)

response = table.query(
    KeyConditionExpression=Key('user_id').eq('123'),
    ScanIndexForward=False  # Descending
)

⬆️⬇️ 5. Sorting Order: ScanIndexForward

⚠️ 6. Sorting with FilterExpression (Limitations)

You cannot sort by non-key attributes. FilterExpressions can filter results after the query, but not order them.

from boto3.dynamodb.conditions import Attr

response = table.query(
    KeyConditionExpression=Key('user_id').eq('123'),
    FilterExpression=Attr('event_type').eq('login'),
    ScanIndexForward=False  # Still only sorts on sort key
)

7. Sorting Without Sort Key: Client-Side Workaround

If your table doesn’t have a sort key or you want to sort by another attribute, use a scan + client-side sort:

response = table.scan()
sorted_items = sorted(response['Items'], key=lambda x: x['score'], reverse=True)

for item in sorted_items:
    print(item)

⚠️ Use with caution — scan() is expensive and slow for large datasets.

8. Full Example

import boto3
from boto3.dynamodb.conditions import Key

def get_user_logs(user_id, descending=False):
    dynamodb = boto3.resource('dynamodb', region_name='us-east-1')
    table = dynamodb.Table('UserLogs')

    response = table.query(
        KeyConditionExpression=Key('user_id').eq(user_id),
        ScanIndexForward=not descending
    )

    return response['Items']

# Usage
logs = get_user_logs('123', descending=True)
for log in logs:
    print(log)

9. Tips and Best Practices

10. Common Pitfalls

✅ 11. Conclusion

Sorting in DynamoDB requires forethought in table design. The sort key is essential if you want to control the order of results. With Python and Boto3:

• Use ScanIndexForward=True/False with query()

• Avoid client-side sorting on large datasets

• Always prefer query() over scan() when sorting is needed

What’s Next?

Want to learn more about:

• Global Secondary Indexes (GSIs) for sorting by different attributes?

• Pagination with query() and scan()?

• Combining sorting and filtering efficiently?