query_test.py

import boto3
import json
import decimal
from boto3.dynamodb.conditions import Key, Attr
from botocore.exceptions import ClientError

# Helper class to convert a DynamoDB item to JSON.
class DecimalEncoder(json.JSONEncoder):
    def default(self, o):
        if isinstance(o, decimal.Decimal):
            if o % 1 > 0:
                return float(o)
            else:
                return int(o)
        return super(DecimalEncoder, self).default(o)

dynamodb = boto3.resource("dynamodb", endpoint_url="https://dynamodb.eu-central-1.amazonaws.com")

table = dynamodb.Table('NetdinoData')

DeviceId = "Netduino1"
UpdateTime = "06/18/2017 00:00:00"
try:
    #  response = table.query(
        #  KeyConditionExpression = Key('year').eq(2016)
    #  )
    response = table.query(
            KeyConditionExpression = Key('DeviceId').eq(DeviceId) & Key('UpdateTime').gte(UpdateTime),
            FilterExpression = Attr('payload.Humidity_1').gt(12)
            )
except ClientError as e:
    print(e.response['Error']['Message'])
else:
    item = response['Items']
    print("GetItem succeeded:")
    print(json.dumps(item, indent=4, cls=DecimalEncoder))