Dynamodb max value

Question

I'm using Dynamodb. I have a simple Employee table with fields like id, name, salary, doj, etc. What is the equivalent query of select max(salary) from employee in dynamodb?

Answer 1

Not sure about boto3 but inboto can be run this way

from boto.dynamodb2.table import Table

table = Table("employee")
values = list(table.query_2(reverse=True, limit=1))
MAXVALUE = values[0][salary]

Answer 2

You can model your schema something like:

• employee_id, as partition-key
• salary, as sort-key of the table or local secondary index.

Then, Query your table for given employee_id, with ScanIndexForward as false, and pick the first returned entry. Since all rows one employee_id are stored in sorted fashion, the first entry in desc order will be the one with highest salary.

You can also keep Limit as 1, in which case DynamoDB will return only one record.

Relevant documentation here.