title: AWS DynamoDB find Item by key in Map attribute (not Partition key)
body: <p>I have a table in DynamoDB where I want to get an Item not by the partition key but by  a key in a Map attribute nested in the table. </p>
  
  <pre><code>{   
      "MyItem": { 
          "Key": "dfcwce",
  
          "NestedMap":
            {
            "map.key" : "value"
            "map.key2" : "value2"
            }
      }
  }
  </code></pre>
  
  <p>I would like to query the item to get the Key of the item by the map.key.</p>