DynamoDB / Client / query

query

DynamoDB.Client.query(**kwargs)

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.

Note

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.

Note

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.

See also: AWS API Documentation

Request Syntax

response = client.query(
    TableName='string',
    IndexName='string',
    Select='ALL_ATTRIBUTES'|'ALL_PROJECTED_ATTRIBUTES'|'SPECIFIC_ATTRIBUTES'|'COUNT',
    AttributesToGet=[
        'string',
    ],
    Limit=123,
    ConsistentRead=True|False,
    KeyConditions={
        'string': {
            'AttributeValueList': [
                {
                    'S': 'string',
                    'N': 'string',
                    'B': b'bytes',
                    'SS': [
                        'string',
                    ],
                    'NS': [
                        'string',
                    ],
                    'BS': [
                        b'bytes',
                    ],
                    'M': {
                        'string': {'... recursive ...'}
                    },
                    'L': [
                        {'... recursive ...'},
                    ],
                    'NULL': True|False,
                    'BOOL': True|False
                },
            ],
            'ComparisonOperator': 'EQ'|'NE'|'IN'|'LE'|'LT'|'GE'|'GT'|'BETWEEN'|'NOT_NULL'|'NULL'|'CONTAINS'|'NOT_CONTAINS'|'BEGINS_WITH'
        }
    },
    QueryFilter={
        'string': {
            'AttributeValueList': [
                {
                    'S': 'string',
                    'N': 'string',
                    'B': b'bytes',
                    'SS': [
                        'string',
                    ],
                    'NS': [
                        'string',
                    ],
                    'BS': [
                        b'bytes',
                    ],
                    'M': {
                        'string': {'... recursive ...'}
                    },
                    'L': [
                        {'... recursive ...'},
                    ],
                    'NULL': True|False,
                    'BOOL': True|False
                },
            ],
            'ComparisonOperator': 'EQ'|'NE'|'IN'|'LE'|'LT'|'GE'|'GT'|'BETWEEN'|'NOT_NULL'|'NULL'|'CONTAINS'|'NOT_CONTAINS'|'BEGINS_WITH'
        }
    },
    ConditionalOperator='AND'|'OR',
    ScanIndexForward=True|False,
    ExclusiveStartKey={
        'string': {
            'S': 'string',
            'N': 'string',
            'B': b'bytes',
            'SS': [
                'string',
            ],
            'NS': [
                'string',
            ],
            'BS': [
                b'bytes',
            ],
            'M': {
                'string': {'... recursive ...'}
            },
            'L': [
                {'... recursive ...'},
            ],
            'NULL': True|False,
            'BOOL': True|False
        }
    },
    ReturnConsumedCapacity='INDEXES'|'TOTAL'|'NONE',
    ProjectionExpression='string',
    FilterExpression='string',
    KeyConditionExpression='string',
    ExpressionAttributeNames={
        'string': 'string'
    },
    ExpressionAttributeValues={
        'string': {
            'S': 'string',
            'N': 'string',
            'B': b'bytes',
            'SS': [
                'string',
            ],
            'NS': [
                'string',
            ],
            'BS': [
                b'bytes',
            ],
            'M': {
                'string': {'... recursive ...'}
            },
            'L': [
                {'... recursive ...'},
            ],
            'NULL': True|False,
            'BOOL': True|False
        }
    }
)

Parameters:

• TableName (string) –

  [REQUIRED]

  The name of the table containing the requested items.

• IndexName (string) – The name of an index to query. This index can be any local secondary index or global secondary index on the table. Note that if you use the IndexName parameter, you must also provide TableName.

• Select (string) –

  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 query a local secondary index, then for each matching item in the index, DynamoDB fetches 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 that have been projected into the index. If the index is configured to project all attributes, this return value is equivalent to specifying ALL_ATTRIBUTES.

  • COUNT - Returns the number of matching items, rather than the matching items themselves. Note that this uses the same quantity of read capacity units as getting the items, and is subject to the same item size calculations.

  • SPECIFIC_ATTRIBUTES - Returns only the attributes listed in ProjectionExpression. This return value is equivalent to specifying ProjectionExpression without specifying any value for Select. If you query or scan 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 fetches each of these attributes from the parent table. This extra fetching incurs additional throughput cost and latency. If you query or scan 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.

  If neither Select nor ProjectionExpression are specified, DynamoDB defaults to ALL_ATTRIBUTES when accessing a table, and ALL_PROJECTED_ATTRIBUTES when accessing an index. You cannot use both Select and ProjectionExpression together in a single request, unless the value for Select is SPECIFIC_ATTRIBUTES. (This usage is equivalent to specifying ProjectionExpression without any value for Select.)

  Note

  If you use the ProjectionExpression parameter, then the value for Select can only be SPECIFIC_ATTRIBUTES. Any other value for Select will return an error.

• AttributesToGet (list) –

  This is a legacy parameter. Use ProjectionExpression instead. For more information, see AttributesToGet in the Amazon DynamoDB Developer Guide.

  • (string) –

• Limit (integer) – The maximum number of items to evaluate (not necessarily the number of matching items). If DynamoDB processes the number of items up to the limit while processing the results, it stops the operation and returns the matching values up to that point, and a key in LastEvaluatedKey to apply in a subsequent operation, so that you can pick up where you left off. Also, if the processed dataset size exceeds 1 MB before DynamoDB reaches this limit, it stops the operation and returns the matching values up to the limit, and a key in LastEvaluatedKey to apply in a subsequent operation to continue the operation. For more information, see Query and Scan in the Amazon DynamoDB Developer Guide.

• ConsistentRead (boolean) –

  Determines the read consistency model: If set to true, then the operation uses strongly consistent reads; otherwise, the operation uses eventually consistent reads.

  Strongly consistent reads are not supported on global secondary indexes. If you query a global secondary index with ConsistentRead set to true, you will receive a ValidationException.

• KeyConditions (dict) –

  This is a legacy parameter. Use KeyConditionExpression instead. For more information, see KeyConditions in the Amazon DynamoDB Developer Guide.

  • (string) –

    • (dict) –

      Represents the selection criteria for a Query or Scan operation:

      • For a Query operation, Condition is used for specifying the KeyConditions to use when querying a table or an index. For KeyConditions, only the following comparison operators are supported: EQ | LE | LT | GE | GT | BEGINS_WITH | BETWEEN Condition is also used in a QueryFilter, which evaluates the query results and returns only the desired values.

      • For a Scan operation, Condition is used in a ScanFilter, which evaluates the scan results and returns only the desired values.

      • AttributeValueList (list) –

        One or more values to evaluate against the supplied attribute. The number of values in the list depends on the ComparisonOperator being used.

        For type Number, value comparisons are numeric.

        String value comparisons for greater than, equals, or less than are based on ASCII character code values. For example, a is greater than A, and a is greater than B. For a list of code values, see http://en.wikipedia.org/wiki/ASCII#ASCII_printable_characters.

        For Binary, DynamoDB treats each byte of the binary data as unsigned when it compares binary values.

        • (dict) –

          Represents the data for an attribute.

          Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.

          For more information, see Data Types in the Amazon DynamoDB Developer Guide.

          • S (string) –

            An attribute of type String. For example:

            "S": "Hello"

          • N (string) –

            An attribute of type Number. For example:

            "N": "123.45"

            Numbers are sent across the network to DynamoDB as strings, to maximize compatibility across languages and libraries. However, DynamoDB treats them as number type attributes for mathematical operations.

          • B (bytes) –

            An attribute of type Binary. For example:

            "B": "dGhpcyB0ZXh0IGlzIGJhc2U2NC1lbmNvZGVk"

          • SS (list) –

            An attribute of type String Set. For example:

            "SS": ["Giraffe", "Hippo" ,"Zebra"]

            • (string) –

          • NS (list) –

            An attribute of type Number Set. For example:

            "NS": ["42.2", "-19", "7.5", "3.14"]

            Numbers are sent across the network to DynamoDB as strings, to maximize compatibility across languages and libraries. However, DynamoDB treats them as number type attributes for mathematical operations.

            • (string) –

          • BS (list) –

            An attribute of type Binary Set. For example:

            "BS": ["U3Vubnk=", "UmFpbnk=", "U25vd3k="]

            • (bytes) –

          • M (dict) –

            An attribute of type Map. For example:

            "M": {"Name": {"S": "Joe"}, "Age": {"N": "35"}}

            • (string) –

              • (dict) –

                Represents the data for an attribute.

                Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.

                For more information, see Data Types in the Amazon DynamoDB Developer Guide.

          • L (list) –

            An attribute of type List. For example:

            "L": [ {"S": "Cookies"} , {"S": "Coffee"}, {"N": "3.14159"}]

            • (dict) –

              Represents the data for an attribute.

              Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.

              For more information, see Data Types in the Amazon DynamoDB Developer Guide.

          • NULL (boolean) –

            An attribute of type Null. For example:

            "NULL": true

          • BOOL (boolean) –

            An attribute of type Boolean. For example:

            "BOOL": true

      • ComparisonOperator (string) – [REQUIRED]

        A comparator for evaluating attributes. For example, equals, greater than, less than, etc.

        The following comparison operators are available:

        EQ | NE | LE | LT | GE | GT | NOT_NULL | NULL | CONTAINS | NOT_CONTAINS | BEGINS_WITH | IN | BETWEEN

        The following are descriptions of each comparison operator.

        • EQ : Equal. EQ is supported for all data types, including lists and maps. AttributeValueList can contain only one AttributeValue element of type String, Number, Binary, String Set, Number Set, or Binary Set. If an item contains an AttributeValue element of a different type than the one provided in the request, the value does not match. For example, {"S":"6"} does not equal {"N":"6"}. Also, {"N":"6"} does not equal {"NS":["6", "2", "1"]}.

        • NE : Not equal. NE is supported for all data types, including lists and maps. AttributeValueList can contain only one AttributeValue of type String, Number, Binary, String Set, Number Set, or Binary Set. If an item contains an AttributeValue of a different type than the one provided in the request, the value does not match. For example, {"S":"6"} does not equal {"N":"6"}. Also, {"N":"6"} does not equal {"NS":["6", "2", "1"]}.

        • LE : Less than or equal. AttributeValueList can contain only one AttributeValue element of type String, Number, or Binary (not a set type). If an item contains an AttributeValue element of a different type than the one provided in the request, the value does not match. For example, {"S":"6"} does not equal {"N":"6"}. Also, {"N":"6"} does not compare to {"NS":["6", "2", "1"]}.

        • LT : Less than. AttributeValueList can contain only one AttributeValue of type String, Number, or Binary (not a set type). If an item contains an AttributeValue element of a different type than the one provided in the request, the value does not match. For example, {"S":"6"} does not equal {"N":"6"}. Also, {"N":"6"} does not compare to {"NS":["6", "2", "1"]}.

        • GE : Greater than or equal. AttributeValueList can contain only one AttributeValue element of type String, Number, or Binary (not a set type). If an item contains an AttributeValue element of a different type than the one provided in the request, the value does not match. For example, {"S":"6"} does not equal {"N":"6"}. Also, {"N":"6"} does not compare to {"NS":["6", "2", "1"]}.

        • GT : Greater than. AttributeValueList can contain only one AttributeValue element of type String, Number, or Binary (not a set type). If an item contains an AttributeValue element of a different type than the one provided in the request, the value does not match. For example, {"S":"6"} does not equal {"N":"6"}. Also, {"N":"6"} does not compare to {"NS":["6", "2", "1"]}.

        • NOT_NULL : The attribute exists. NOT_NULL is supported for all data types, including lists and maps.

        Note

        This operator tests for the existence of an attribute, not its data type. If the data type of attribute “ a” is null, and you evaluate it using NOT_NULL, the result is a Boolean true. This result is because the attribute “ a” exists; its data type is not relevant to the NOT_NULL comparison operator.

        • NULL : The attribute does not exist. NULL is supported for all data types, including lists and maps.

        Note

        This operator tests for the nonexistence of an attribute, not its data type. If the data type of attribute “ a” is null, and you evaluate it using NULL, the result is a Boolean false. This is because the attribute “ a” exists; its data type is not relevant to the NULL comparison operator.

        • CONTAINS : Checks for a subsequence, or value in a set. AttributeValueList can contain only one AttributeValue element of type String, Number, or Binary (not a set type). If the target attribute of the comparison is of type String, then the operator checks for a substring match. If the target attribute of the comparison is of type Binary, then the operator looks for a subsequence of the target that matches the input. If the target attribute of the comparison is a set (” SS”, “ NS”, or “ BS”), then the operator evaluates to true if it finds an exact match with any member of the set. CONTAINS is supported for lists: When evaluating “ a CONTAINS b”, “ a” can be a list; however, “ b” cannot be a set, a map, or a list.

        • NOT_CONTAINS : Checks for absence of a subsequence, or absence of a value in a set. AttributeValueList can contain only one AttributeValue element of type String, Number, or Binary (not a set type). If the target attribute of the comparison is a String, then the operator checks for the absence of a substring match. If the target attribute of the comparison is Binary, then the operator checks for the absence of a subsequence of the target that matches the input. If the target attribute of the comparison is a set (” SS”, “ NS”, or “ BS”), then the operator evaluates to true if it does not find an exact match with any member of the set. NOT_CONTAINS is supported for lists: When evaluating “ a NOT CONTAINS b”, “ a” can be a list; however, “ b” cannot be a set, a map, or a list.

        • BEGINS_WITH : Checks for a prefix. AttributeValueList can contain only one AttributeValue of type String or Binary (not a Number or a set type). The target attribute of the comparison must be of type String or Binary (not a Number or a set type).

        • IN : Checks for matching elements in a list. AttributeValueList can contain one or more AttributeValue elements of type String, Number, or Binary. These attributes are compared against an existing attribute of an item. If any elements of the input are equal to the item attribute, the expression evaluates to true.

        • BETWEEN : Greater than or equal to the first value, and less than or equal to the second value. AttributeValueList must contain two AttributeValue elements of the same type, either String, Number, or Binary (not a set type). A target attribute matches if the target value is greater than, or equal to, the first element and less than, or equal to, the second element. If an item contains an AttributeValue element of a different type than the one provided in the request, the value does not match. For example, {"S":"6"} does not compare to {"N":"6"}. Also, {"N":"6"} does not compare to {"NS":["6", "2", "1"]}

        For usage examples of AttributeValueList and ComparisonOperator, see Legacy Conditional Parameters in the Amazon DynamoDB Developer Guide.

• QueryFilter (dict) –

  This is a legacy parameter. Use FilterExpression instead. For more information, see QueryFilter in the Amazon DynamoDB Developer Guide.

  • (string) –

    • (dict) –

      Represents the selection criteria for a Query or Scan operation:

      • For a Query operation, Condition is used for specifying the KeyConditions to use when querying a table or an index. For KeyConditions, only the following comparison operators are supported: EQ | LE | LT | GE | GT | BEGINS_WITH | BETWEEN Condition is also used in a QueryFilter, which evaluates the query results and returns only the desired values.

      • For a Scan operation, Condition is used in a ScanFilter, which evaluates the scan results and returns only the desired values.

      • AttributeValueList (list) –

        One or more values to evaluate against the supplied attribute. The number of values in the list depends on the ComparisonOperator being used.

        For type Number, value comparisons are numeric.

        String value comparisons for greater than, equals, or less than are based on ASCII character code values. For example, a is greater than A, and a is greater than B. For a list of code values, see http://en.wikipedia.org/wiki/ASCII#ASCII_printable_characters.

        For Binary, DynamoDB treats each byte of the binary data as unsigned when it compares binary values.

        • (dict) –

          Represents the data for an attribute.

          Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.

          For more information, see Data Types in the Amazon DynamoDB Developer Guide.

          • S (string) –

            An attribute of type String. For example:

            "S": "Hello"

          • N (string) –

            An attribute of type Number. For example:

            "N": "123.45"

            Numbers are sent across the network to DynamoDB as strings, to maximize compatibility across languages and libraries. However, DynamoDB treats them as number type attributes for mathematical operations.

          • B (bytes) –

            An attribute of type Binary. For example:

            "B": "dGhpcyB0ZXh0IGlzIGJhc2U2NC1lbmNvZGVk"

          • SS (list) –

            An attribute of type String Set. For example:

            "SS": ["Giraffe", "Hippo" ,"Zebra"]

            • (string) –

          • NS (list) –

            An attribute of type Number Set. For example:

            "NS": ["42.2", "-19", "7.5", "3.14"]

            Numbers are sent across the network to DynamoDB as strings, to maximize compatibility across languages and libraries. However, DynamoDB treats them as number type attributes for mathematical operations.

            • (string) –

          • BS (list) –

            An attribute of type Binary Set. For example:

            "BS": ["U3Vubnk=", "UmFpbnk=", "U25vd3k="]

            • (bytes) –

          • M (dict) –

            An attribute of type Map. For example:

            "M": {"Name": {"S": "Joe"}, "Age": {"N": "35"}}

            • (string) –

              • (dict) –

                Represents the data for an attribute.

                Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.

                For more information, see Data Types in the Amazon DynamoDB Developer Guide.

          • L (list) –

            An attribute of type List. For example:

            "L": [ {"S": "Cookies"} , {"S": "Coffee"}, {"N": "3.14159"}]

            • (dict) –

              Represents the data for an attribute.

              Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.

              For more information, see Data Types in the Amazon DynamoDB Developer Guide.

          • NULL (boolean) –

            An attribute of type Null. For example:

            "NULL": true

          • BOOL (boolean) –

            An attribute of type Boolean. For example:

            "BOOL": true

      • ComparisonOperator (string) – [REQUIRED]

        A comparator for evaluating attributes. For example, equals, greater than, less than, etc.

        The following comparison operators are available:

        EQ | NE | LE | LT | GE | GT | NOT_NULL | NULL | CONTAINS | NOT_CONTAINS | BEGINS_WITH | IN | BETWEEN

        The following are descriptions of each comparison operator.

        • EQ : Equal. EQ is supported for all data types, including lists and maps. AttributeValueList can contain only one AttributeValue element of type String, Number, Binary, String Set, Number Set, or Binary Set. If an item contains an AttributeValue element of a different type than the one provided in the request, the value does not match. For example, {"S":"6"} does not equal {"N":"6"}. Also, {"N":"6"} does not equal {"NS":["6", "2", "1"]}.

        • NE : Not equal. NE is supported for all data types, including lists and maps. AttributeValueList can contain only one AttributeValue of type String, Number, Binary, String Set, Number Set, or Binary Set. If an item contains an AttributeValue of a different type than the one provided in the request, the value does not match. For example, {"S":"6"} does not equal {"N":"6"}. Also, {"N":"6"} does not equal {"NS":["6", "2", "1"]}.

        • LE : Less than or equal. AttributeValueList can contain only one AttributeValue element of type String, Number, or Binary (not a set type). If an item contains an AttributeValue element of a different type than the one provided in the request, the value does not match. For example, {"S":"6"} does not equal {"N":"6"}. Also, {"N":"6"} does not compare to {"NS":["6", "2", "1"]}.

        • LT : Less than. AttributeValueList can contain only one AttributeValue of type String, Number, or Binary (not a set type). If an item contains an AttributeValue element of a different type than the one provided in the request, the value does not match. For example, {"S":"6"} does not equal {"N":"6"}. Also, {"N":"6"} does not compare to {"NS":["6", "2", "1"]}.

        • GE : Greater than or equal. AttributeValueList can contain only one AttributeValue element of type String, Number, or Binary (not a set type). If an item contains an AttributeValue element of a different type than the one provided in the request, the value does not match. For example, {"S":"6"} does not equal {"N":"6"}. Also, {"N":"6"} does not compare to {"NS":["6", "2", "1"]}.

        • GT : Greater than. AttributeValueList can contain only one AttributeValue element of type String, Number, or Binary (not a set type). If an item contains an AttributeValue element of a different type than the one provided in the request, the value does not match. For example, {"S":"6"} does not equal {"N":"6"}. Also, {"N":"6"} does not compare to {"NS":["6", "2", "1"]}.

        • NOT_NULL : The attribute exists. NOT_NULL is supported for all data types, including lists and maps.

        Note

        This operator tests for the existence of an attribute, not its data type. If the data type of attribute “ a” is null, and you evaluate it using NOT_NULL, the result is a Boolean true. This result is because the attribute “ a” exists; its data type is not relevant to the NOT_NULL comparison operator.

        • NULL : The attribute does not exist. NULL is supported for all data types, including lists and maps.

        Note

        This operator tests for the nonexistence of an attribute, not its data type. If the data type of attribute “ a” is null, and you evaluate it using NULL, the result is a Boolean false. This is because the attribute “ a” exists; its data type is not relevant to the NULL comparison operator.

        • CONTAINS : Checks for a subsequence, or value in a set. AttributeValueList can contain only one AttributeValue element of type String, Number, or Binary (not a set type). If the target attribute of the comparison is of type String, then the operator checks for a substring match. If the target attribute of the comparison is of type Binary, then the operator looks for a subsequence of the target that matches the input. If the target attribute of the comparison is a set (” SS”, “ NS”, or “ BS”), then the operator evaluates to true if it finds an exact match with any member of the set. CONTAINS is supported for lists: When evaluating “ a CONTAINS b”, “ a” can be a list; however, “ b” cannot be a set, a map, or a list.

        • NOT_CONTAINS : Checks for absence of a subsequence, or absence of a value in a set. AttributeValueList can contain only one AttributeValue element of type String, Number, or Binary (not a set type). If the target attribute of the comparison is a String, then the operator checks for the absence of a substring match. If the target attribute of the comparison is Binary, then the operator checks for the absence of a subsequence of the target that matches the input. If the target attribute of the comparison is a set (” SS”, “ NS”, or “ BS”), then the operator evaluates to true if it does not find an exact match with any member of the set. NOT_CONTAINS is supported for lists: When evaluating “ a NOT CONTAINS b”, “ a” can be a list; however, “ b” cannot be a set, a map, or a list.

        • BEGINS_WITH : Checks for a prefix. AttributeValueList can contain only one AttributeValue of type String or Binary (not a Number or a set type). The target attribute of the comparison must be of type String or Binary (not a Number or a set type).

        • IN : Checks for matching elements in a list. AttributeValueList can contain one or more AttributeValue elements of type String, Number, or Binary. These attributes are compared against an existing attribute of an item. If any elements of the input are equal to the item attribute, the expression evaluates to true.

        • BETWEEN : Greater than or equal to the first value, and less than or equal to the second value. AttributeValueList must contain two AttributeValue elements of the same type, either String, Number, or Binary (not a set type). A target attribute matches if the target value is greater than, or equal to, the first element and less than, or equal to, the second element. If an item contains an AttributeValue element of a different type than the one provided in the request, the value does not match. For example, {"S":"6"} does not compare to {"N":"6"}. Also, {"N":"6"} does not compare to {"NS":["6", "2", "1"]}

        For usage examples of AttributeValueList and ComparisonOperator, see Legacy Conditional Parameters in the Amazon DynamoDB Developer Guide.

• ConditionalOperator (string) – This is a legacy parameter. Use FilterExpression instead. For more information, see ConditionalOperator in the Amazon DynamoDB Developer Guide.

• ScanIndexForward (boolean) –

  Specifies the order for index traversal: If true (default), the traversal is performed in ascending order; if false, the traversal is performed in descending order.

  Items with the same partition key value are stored in sorted order by sort key. If the sort key data type is Number, the results are stored in numeric order. For type String, the results are stored in order of UTF-8 bytes. For type Binary, DynamoDB treats each byte of the binary data as unsigned.

  If ScanIndexForward is true, DynamoDB returns the results in the order in which they are stored (by sort key value). This is the default behavior. If ScanIndexForward is false, DynamoDB reads the results in reverse order by sort key value, and then returns the results to the client.

• ExclusiveStartKey (dict) –

  The primary key of the first item that this operation will evaluate. Use the value that was returned for LastEvaluatedKey in the previous operation.

  The data type for ExclusiveStartKey must be String, Number, or Binary. No set data types are allowed.

  • (string) –

    • (dict) –

      Represents the data for an attribute.

      Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.

      For more information, see Data Types in the Amazon DynamoDB Developer Guide.

      • S (string) –

        An attribute of type String. For example:

        "S": "Hello"

      • N (string) –

        An attribute of type Number. For example:

        "N": "123.45"

        Numbers are sent across the network to DynamoDB as strings, to maximize compatibility across languages and libraries. However, DynamoDB treats them as number type attributes for mathematical operations.

      • B (bytes) –

        An attribute of type Binary. For example:

        "B": "dGhpcyB0ZXh0IGlzIGJhc2U2NC1lbmNvZGVk"

      • SS (list) –

        An attribute of type String Set. For example:

        "SS": ["Giraffe", "Hippo" ,"Zebra"]

        • (string) –

      • NS (list) –

        An attribute of type Number Set. For example:

        "NS": ["42.2", "-19", "7.5", "3.14"]

        Numbers are sent across the network to DynamoDB as strings, to maximize compatibility across languages and libraries. However, DynamoDB treats them as number type attributes for mathematical operations.

        • (string) –

      • BS (list) –

        An attribute of type Binary Set. For example:

        "BS": ["U3Vubnk=", "UmFpbnk=", "U25vd3k="]

        • (bytes) –

      • M (dict) –

        An attribute of type Map. For example:

        "M": {"Name": {"S": "Joe"}, "Age": {"N": "35"}}

        • (string) –

          • (dict) –

            Represents the data for an attribute.

            Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.

            For more information, see Data Types in the Amazon DynamoDB Developer Guide.

      • L (list) –

        An attribute of type List. For example:

        "L": [ {"S": "Cookies"} , {"S": "Coffee"}, {"N": "3.14159"}]

        • (dict) –

          Represents the data for an attribute.

          Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.

          For more information, see Data Types in the Amazon DynamoDB Developer Guide.

      • NULL (boolean) –

        An attribute of type Null. For example:

        "NULL": true

      • BOOL (boolean) –

        An attribute of type Boolean. For example:

        "BOOL": true

• ReturnConsumedCapacity (string) –

  Determines the level of detail about either provisioned or on-demand throughput consumption that is returned in the response:

  • INDEXES - The response includes the aggregate ConsumedCapacity for the operation, together with ConsumedCapacity for each table and secondary index that was accessed. Note that some operations, such as GetItem and BatchGetItem, do not access any indexes at all. In these cases, specifying INDEXES will only return ConsumedCapacity information for table(s).

  • TOTAL - The response includes only the aggregate ConsumedCapacity for the operation.

  • NONE - No ConsumedCapacity details are included in the response.

• ProjectionExpression (string) –

  A string that identifies one or more attributes to retrieve from the table. These attributes can include scalars, sets, or elements of a JSON document. The attributes in the expression must be separated by commas.

  If no attribute names are specified, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result.

  For more information, see Accessing Item Attributes in the Amazon DynamoDB Developer Guide.

• FilterExpression (string) –

  A string that contains conditions that DynamoDB applies after the Query operation, but before the data is returned to you. Items that do not satisfy the FilterExpression criteria are not returned.

  A FilterExpression does not allow key attributes. You cannot define a filter expression based on a partition key or a sort key.

  Note

  A FilterExpression is applied after the items have already been read; the process of filtering does not consume any additional read capacity units.

  For more information, see Filter Expressions in the Amazon DynamoDB Developer Guide.

• KeyConditionExpression (string) –

  The condition that specifies the key values for items to be retrieved by the Query action.

  The condition must perform an equality test on a single partition key value.

  The condition can optionally perform one of several comparison tests on a single sort key value. This allows Query to retrieve one item with a given partition key value and sort key value, or several items that have the same partition key value but different sort key values.

  The partition key equality test is required, and must be specified in the following format:

  partitionKeyName = :partitionkeyval

  If you also want to provide a condition for the sort key, it must be combined using AND with the condition for the sort key. Following is an example, using the = comparison operator for the sort key:

  partitionKeyName = :partitionkeyval AND sortKeyName = :sortkeyval

  Valid comparisons for the sort key condition are as follows:

  • sortKeyName = :sortkeyval - true if the sort key value is equal to :sortkeyval.

  • sortKeyName < :sortkeyval - true if the sort key value is less than :sortkeyval.

  • sortKeyName <= :sortkeyval - true if the sort key value is less than or equal to :sortkeyval.

  • sortKeyName > :sortkeyval - true if the sort key value is greater than :sortkeyval.

  • sortKeyName >= :sortkeyval - true if the sort key value is greater than or equal to :sortkeyval.

  • sortKeyName BETWEEN :sortkeyval1 AND :sortkeyval2 - true if the sort key value is greater than or equal to :sortkeyval1, and less than or equal to :sortkeyval2.

  • begins_with ( sortKeyName, :sortkeyval ) - true if the sort key value begins with a particular operand. (You cannot use this function with a sort key that is of type Number.) Note that the function name begins_with is case-sensitive.

  Use the ExpressionAttributeValues parameter to replace tokens such as :partitionval and :sortval with actual values at runtime.

  You can optionally use the ExpressionAttributeNames parameter to replace the names of the partition key and sort key with placeholder tokens. This option might be necessary if an attribute name conflicts with a DynamoDB reserved word. For example, the following KeyConditionExpression parameter causes an error because Size is a reserved word:

  • Size = :myval

  To work around this, define a placeholder (such a #S) to represent the attribute name Size. KeyConditionExpression then is as follows:

  • #S = :myval

  For a list of reserved words, see Reserved Words in the Amazon DynamoDB Developer Guide.

  For more information on ExpressionAttributeNames and ExpressionAttributeValues, see Using Placeholders for Attribute Names and Values in the Amazon DynamoDB Developer Guide.

• ExpressionAttributeNames (dict) –

  One or more substitution tokens for attribute names in an expression. The following are some use cases for using ExpressionAttributeNames:

  • To access an attribute whose name conflicts with a DynamoDB reserved word.

  • To create a placeholder for repeating occurrences of an attribute name in an expression.

  • To prevent special characters in an attribute name from being misinterpreted in an expression.

  Use the # character in an expression to dereference an attribute name. For example, consider the following attribute name:

  • Percentile

  The name of this attribute conflicts with a reserved word, so it cannot be used directly in an expression. (For the complete list of reserved words, see Reserved Words in the Amazon DynamoDB Developer Guide). To work around this, you could specify the following for ExpressionAttributeNames:

  • {"#P":"Percentile"}

  You could then use this substitution in an expression, as in this example:

  • #P = :val

  Note

  Tokens that begin with the : character are expression attribute values, which are placeholders for the actual value at runtime.

  For more information on expression attribute names, see Specifying Item Attributes in the Amazon DynamoDB Developer Guide.

  • (string) –

    • (string) –

• ExpressionAttributeValues (dict) –

  One or more values that can be substituted in an expression.

  Use the : (colon) character in an expression to dereference an attribute value. For example, suppose that you wanted to check whether the value of the ProductStatus attribute was one of the following:

  Available | Backordered | Discontinued

  You would first need to specify ExpressionAttributeValues as follows:

  { ":avail":{"S":"Available"}, ":back":{"S":"Backordered"}, ":disc":{"S":"Discontinued"} }

  You could then use these values in an expression, such as this:

  ProductStatus IN (:avail, :back, :disc)

  For more information on expression attribute values, see Specifying Conditions in the Amazon DynamoDB Developer Guide.

  • (string) –

    • (dict) –

      Represents the data for an attribute.

      Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.

      For more information, see Data Types in the Amazon DynamoDB Developer Guide.

      • S (string) –

        An attribute of type String. For example:

        "S": "Hello"

      • N (string) –

        An attribute of type Number. For example:

        "N": "123.45"

        Numbers are sent across the network to DynamoDB as strings, to maximize compatibility across languages and libraries. However, DynamoDB treats them as number type attributes for mathematical operations.

      • B (bytes) –

        An attribute of type Binary. For example:

        "B": "dGhpcyB0ZXh0IGlzIGJhc2U2NC1lbmNvZGVk"

      • SS (list) –

        An attribute of type String Set. For example:

        "SS": ["Giraffe", "Hippo" ,"Zebra"]

        • (string) –

      • NS (list) –

        An attribute of type Number Set. For example:

        "NS": ["42.2", "-19", "7.5", "3.14"]

        Numbers are sent across the network to DynamoDB as strings, to maximize compatibility across languages and libraries. However, DynamoDB treats them as number type attributes for mathematical operations.

        • (string) –

      • BS (list) –

        An attribute of type Binary Set. For example:

        "BS": ["U3Vubnk=", "UmFpbnk=", "U25vd3k="]

        • (bytes) –

      • M (dict) –

        An attribute of type Map. For example:

        "M": {"Name": {"S": "Joe"}, "Age": {"N": "35"}}

        • (string) –

          • (dict) –

            Represents the data for an attribute.

            Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.

            For more information, see Data Types in the Amazon DynamoDB Developer Guide.

      • L (list) –

        An attribute of type List. For example:

        "L": [ {"S": "Cookies"} , {"S": "Coffee"}, {"N": "3.14159"}]

        • (dict) –

          Represents the data for an attribute.

          Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.

          For more information, see Data Types in the Amazon DynamoDB Developer Guide.

      • NULL (boolean) –

        An attribute of type Null. For example:

        "NULL": true

      • BOOL (boolean) –

        An attribute of type Boolean. For example:

        "BOOL": true

Return type:

dict

Returns:

Response Syntax

{
    'Items': [
        {
            'string': {
                'S': 'string',
                'N': 'string',
                'B': b'bytes',
                'SS': [
                    'string',
                ],
                'NS': [
                    'string',
                ],
                'BS': [
                    b'bytes',
                ],
                'M': {
                    'string': {'... recursive ...'}
                },
                'L': [
                    {'... recursive ...'},
                ],
                'NULL': True|False,
                'BOOL': True|False
            }
        },
    ],
    'Count': 123,
    'ScannedCount': 123,
    'LastEvaluatedKey': {
        'string': {
            'S': 'string',
            'N': 'string',
            'B': b'bytes',
            'SS': [
                'string',
            ],
            'NS': [
                'string',
            ],
            'BS': [
                b'bytes',
            ],
            'M': {
                'string': {'... recursive ...'}
            },
            'L': [
                {'... recursive ...'},
            ],
            'NULL': True|False,
            'BOOL': True|False
        }
    },
    'ConsumedCapacity': {
        'TableName': 'string',
        'CapacityUnits': 123.0,
        'ReadCapacityUnits': 123.0,
        'WriteCapacityUnits': 123.0,
        'Table': {
            'ReadCapacityUnits': 123.0,
            'WriteCapacityUnits': 123.0,
            'CapacityUnits': 123.0
        },
        'LocalSecondaryIndexes': {
            'string': {
                'ReadCapacityUnits': 123.0,
                'WriteCapacityUnits': 123.0,
                'CapacityUnits': 123.0
            }
        },
        'GlobalSecondaryIndexes': {
            'string': {
                'ReadCapacityUnits': 123.0,
                'WriteCapacityUnits': 123.0,
                'CapacityUnits': 123.0
            }
        }
    }
}

Response Structure

• (dict) –

  Represents the output of a Query operation.

  • Items (list) –

    An array of item attributes that match the query criteria. Each element in this array consists of an attribute name and the value for that attribute.

    • (dict) –

      • (string) –

        • (dict) –

          Represents the data for an attribute.

          Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.

          For more information, see Data Types in the Amazon DynamoDB Developer Guide.

          • S (string) –

            An attribute of type String. For example:

            "S": "Hello"

          • N (string) –

            An attribute of type Number. For example:

            "N": "123.45"

            Numbers are sent across the network to DynamoDB as strings, to maximize compatibility across languages and libraries. However, DynamoDB treats them as number type attributes for mathematical operations.

          • B (bytes) –

            An attribute of type Binary. For example:

            "B": "dGhpcyB0ZXh0IGlzIGJhc2U2NC1lbmNvZGVk"

          • SS (list) –

            An attribute of type String Set. For example:

            "SS": ["Giraffe", "Hippo" ,"Zebra"]

            • (string) –

          • NS (list) –

            An attribute of type Number Set. For example:

            "NS": ["42.2", "-19", "7.5", "3.14"]

            Numbers are sent across the network to DynamoDB as strings, to maximize compatibility across languages and libraries. However, DynamoDB treats them as number type attributes for mathematical operations.

            • (string) –

          • BS (list) –

            An attribute of type Binary Set. For example:

            "BS": ["U3Vubnk=", "UmFpbnk=", "U25vd3k="]

            • (bytes) –

          • M (dict) –

            An attribute of type Map. For example:

            "M": {"Name": {"S": "Joe"}, "Age": {"N": "35"}}

            • (string) –

              • (dict) –

                Represents the data for an attribute.

                Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.

                For more information, see Data Types in the Amazon DynamoDB Developer Guide.

          • L (list) –

            An attribute of type List. For example:

            "L": [ {"S": "Cookies"} , {"S": "Coffee"}, {"N": "3.14159"}]

            • (dict) –

              Represents the data for an attribute.

              Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.

              For more information, see Data Types in the Amazon DynamoDB Developer Guide.

          • NULL (boolean) –

            An attribute of type Null. For example:

            "NULL": true

          • BOOL (boolean) –

            An attribute of type Boolean. For example:

            "BOOL": true

  • Count (integer) –

    The number of items in the response.

    If you used a QueryFilter in the request, then Count is the number of items returned after the filter was applied, and ScannedCount is the number of matching items before the filter was applied.

    If you did not use a filter in the request, then Count and ScannedCount are the same.

  • ScannedCount (integer) –

    The number of items evaluated, before any QueryFilter is applied. A high ScannedCount value with few, or no, Count results indicates an inefficient Query operation. For more information, see Count and ScannedCount in the Amazon DynamoDB Developer Guide.

    If you did not use a filter in the request, then ScannedCount is the same as Count.

  • LastEvaluatedKey (dict) –

    The primary key of the item where the operation stopped, inclusive of the previous result set. Use this value to start a new operation, excluding this value in the new request.

    If LastEvaluatedKey is empty, then the “last page” of results has been processed and there is no more data to be retrieved.

    If LastEvaluatedKey is not empty, it does not necessarily mean that there is more data in the result set. The only way to know when you have reached the end of the result set is when LastEvaluatedKey is empty.

    • (string) –

      • (dict) –

        Represents the data for an attribute.

        Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.

        For more information, see Data Types in the Amazon DynamoDB Developer Guide.

        • S (string) –

          An attribute of type String. For example:

          "S": "Hello"

        • N (string) –

          An attribute of type Number. For example:

          "N": "123.45"

          Numbers are sent across the network to DynamoDB as strings, to maximize compatibility across languages and libraries. However, DynamoDB treats them as number type attributes for mathematical operations.

        • B (bytes) –

          An attribute of type Binary. For example:

          "B": "dGhpcyB0ZXh0IGlzIGJhc2U2NC1lbmNvZGVk"

        • SS (list) –

          An attribute of type String Set. For example:

          "SS": ["Giraffe", "Hippo" ,"Zebra"]

          • (string) –

        • NS (list) –

          An attribute of type Number Set. For example:

          "NS": ["42.2", "-19", "7.5", "3.14"]

          Numbers are sent across the network to DynamoDB as strings, to maximize compatibility across languages and libraries. However, DynamoDB treats them as number type attributes for mathematical operations.

          • (string) –

        • BS (list) –

          An attribute of type Binary Set. For example:

          "BS": ["U3Vubnk=", "UmFpbnk=", "U25vd3k="]

          • (bytes) –

        • M (dict) –

          An attribute of type Map. For example:

          "M": {"Name": {"S": "Joe"}, "Age": {"N": "35"}}

          • (string) –

            • (dict) –

              Represents the data for an attribute.

              Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.

              For more information, see Data Types in the Amazon DynamoDB Developer Guide.

        • L (list) –

          An attribute of type List. For example:

          "L": [ {"S": "Cookies"} , {"S": "Coffee"}, {"N": "3.14159"}]

          • (dict) –

            Represents the data for an attribute.

            Each attribute value is described as a name-value pair. The name is the data type, and the value is the data itself.

            For more information, see Data Types in the Amazon DynamoDB Developer Guide.

        • NULL (boolean) –

          An attribute of type Null. For example:

          "NULL": true

        • BOOL (boolean) –

          An attribute of type Boolean. For example:

          "BOOL": true

  • ConsumedCapacity (dict) –

    The capacity units consumed by the Query operation. The data returned includes the total provisioned throughput consumed, along with statistics for the table and any indexes involved in the operation. ConsumedCapacity is only returned if the ReturnConsumedCapacity parameter was specified. For more information, see Provisioned Throughput in the Amazon DynamoDB Developer Guide.

    • TableName (string) –

      The name of the table that was affected by the operation.

    • CapacityUnits (float) –

      The total number of capacity units consumed by the operation.

    • ReadCapacityUnits (float) –

      The total number of read capacity units consumed by the operation.

    • WriteCapacityUnits (float) –

      The total number of write capacity units consumed by the operation.

    • Table (dict) –

      The amount of throughput consumed on the table affected by the operation.

      • ReadCapacityUnits (float) –

        The total number of read capacity units consumed on a table or an index.

      • WriteCapacityUnits (float) –

        The total number of write capacity units consumed on a table or an index.

      • CapacityUnits (float) –

        The total number of capacity units consumed on a table or an index.

    • LocalSecondaryIndexes (dict) –

      The amount of throughput consumed on each local index affected by the operation.

      • (string) –

        • (dict) –

          Represents the amount of provisioned throughput capacity consumed on a table or an index.

          • ReadCapacityUnits (float) –

            The total number of read capacity units consumed on a table or an index.

          • WriteCapacityUnits (float) –

            The total number of write capacity units consumed on a table or an index.

          • CapacityUnits (float) –

            The total number of capacity units consumed on a table or an index.

    • GlobalSecondaryIndexes (dict) –

      The amount of throughput consumed on each global index affected by the operation.

      • (string) –

        • (dict) –

          Represents the amount of provisioned throughput capacity consumed on a table or an index.

          • ReadCapacityUnits (float) –

            The total number of read capacity units consumed on a table or an index.

          • WriteCapacityUnits (float) –

            The total number of write capacity units consumed on a table or an index.

          • CapacityUnits (float) –

            The total number of capacity units consumed on a table or an index.

Exceptions

• DynamoDB.Client.exceptions.ProvisionedThroughputExceededException

• DynamoDB.Client.exceptions.ResourceNotFoundException

• DynamoDB.Client.exceptions.RequestLimitExceeded

• DynamoDB.Client.exceptions.InternalServerError

Examples

This example queries items in the Music table. The table has a partition key and sort key (Artist and SongTitle), but this query only specifies the partition key value. It returns song titles by the artist named “No One You Know”.

response = client.query(
    ExpressionAttributeValues={
        ':v1': {
            'S': 'No One You Know',
        },
    },
    KeyConditionExpression='Artist = :v1',
    ProjectionExpression='SongTitle',
    TableName='Music',
)

print(response)

Expected Output:

{
    'ConsumedCapacity': {
    },
    'Count': 2,
    'Items': [
        {
            'SongTitle': {
                'S': 'Call Me Today',
            },
        },
    ],
    'ScannedCount': 2,
    'ResponseMetadata': {
        '...': '...',
    },
}