The attributes to be returned in the result. You can retrieve all item attributes, specific item attributes, the count of matching items, or
in the case of an index, some or all of the attributes projected into the index.
- ALL_ATTRIBUTES: Returns all of the item attributes from the specified table or index. If you are querying a local secondary index, then for each matching item in the index DynamoDB will fetch the entire item from the parent table. If the index is configured to project all item attributes, then all of the data can be obtained from the local secondary index, and no fetching is required..
- ALL_PROJECTED_ATTRIBUTES: Allowed only when querying an index. Retrieves all attributes which have been projected into the index. If the index is configured to project all attributes, this is equivalent to specifying ALL_ATTRIBUTES.
- COUNT: Returns the number of matching items, rather than the matching items themselves.
- SPECIFIC_ATTRIBUTES : Returns only the attributes listed in AttributesToGet. This is equivalent to specifying AttributesToGet without specifying any value for Select. If you are querying a local secondary index and request only attributes that are projected into that index, the operation will read only the index and not the table. If any of the requested attributes are not projected into the local secondary index, DynamoDB will fetch each of these attributes from the parent table. This extra fetching incurs additional throughput cost and latency. If you are querying a global secondary index, you can only request attributes that are projected into the index. Global secondary index queries cannot fetch attributes from the parent table.
Constraints:

C# |
public string Select { get; set; }