You must provide the name of the partition key attribute and a single value for that attribute.
Query returns all items with that partition key value. Optionally, you can provide a sort key attribute and use a comparison operator to refine the search results.
Use the
KeyConditionExpression parameter to provide a specific value for the partition key. The
Query operation will return all of the items from the table or index with that partition key value. You can optionally narrow the scope of the
Query operation by specifying a sort key value and a comparison operator in
KeyConditionExpression. To further refine the
Query results, you can optionally provide a
FilterExpression. A
FilterExpression determines which items within the results should be returned to you. All of the other results are discarded.
A
Query operation always returns a result set. If no matching items are found, the result set will be empty. Queries that do not return results consume the minimum number of read capacity units for that type of read operation.
DynamoDB calculates the number of read capacity units consumed based on item size, not on the amount of data that is returned to an application. The number of capacity units consumed will be the same whether you request all of the attributes (the default behavior) or just some of them (using a projection expression). The number will also be the same whether or not you use a
FilterExpression.
Query results are always sorted by the sort key value. If the data type of the sort key is Number, the results are returned in numeric order; otherwise, the results are returned in order of UTF-8 bytes. By default, the sort order is ascending. To reverse the order, set the
ScanIndexForward parameter to false.
A single
Query operation will read up to the maximum number of items set (if using the
Limit parameter) or a maximum of 1 MB of data and then apply any filtering to the results using
FilterExpression. If
LastEvaluatedKey is present in the response, you will need to paginate the result set. For more information, see
Paginating the Results in the
Amazon DynamoDB Developer Guide.
FilterExpression is applied after a
Query finishes, but before the results are returned. A
FilterExpression cannot contain partition key or sort key attributes. You need to specify those attributes in the
KeyConditionExpression.
A
Query operation can return an empty result set and a
LastEvaluatedKey if all the items read for the page of results are filtered out.
You can query a table, a local secondary index, or a global secondary index. For a query on a table or on a local secondary index, you can set the
ConsistentRead parameter to
true and obtain a strongly consistent result. Global secondary indexes support eventually consistent reads only, so do not specify
ConsistentRead when querying a global secondary index.
This cmdlet automatically pages all available results to the pipeline - parameters related to iteration are only needed if you want to manually control the paginated output. To disable autopagination, use -NoAutoIteration.