Select

Description

The Select operation returns a set of Attributes for ItemNames that match the select expression. Select is similar to the standard SQL SELECT statement.

The total size of the response cannot exceed 1 MB in total size. Amazon SimpleDB automatically adjusts the number of items returned per page to enforce this limit. For example, even if you ask to retrieve 2500 items, but each individual item is 10 kB in size, the system returns 100 items and an appropriate next token so you can get the next page of results.

For information on how to construct select expressions, see Using Select to Create Amazon SimpleDB Queries.

Note

	Note
Operations that run longer than 5 seconds return a time-out error response or a partial or empty result set. Partial and empty result sets contains a next token which allow you to continue the operation from where it left off. Responses larger than one megabyte return a partial result set. Your application should not excessively retry queries that return `RequestTimeout` errors. If you receive too many `RequestTimeout` errors, reduce the complexity of your query expression. When designing your application, keep in mind that Amazon SimpleDB does not guarantee how attributes are ordered in the returned response. For information about limits that affect Select, see Amazon SimpleDB Limits.

Operations that run longer than 5 seconds return a time-out error response or a partial or empty result set. Partial and empty result sets contains a next token which allow you to continue the operation from where it left off.

Responses larger than one megabyte return a partial result set.

Your application should not excessively retry queries that return RequestTimeout errors. If you receive too many RequestTimeout errors, reduce the complexity of your query expression.

When designing your application, keep in mind that Amazon SimpleDB does not guarantee how attributes are ordered in the returned response.

For information about limits that affect Select, see Amazon SimpleDB Limits.

Request Parameters

Name Description Required

Name	Description	Required
`SelectExpression`	The expression used to query the domain. Type: String Default: None	Yes
`NextToken`	String that tells Amazon SimpleDB where to start the next list of ItemNames. Type: String Default: None	No

SelectExpression

The expression used to query the domain.

Type: String

Default: None

Yes

NextToken

String that tells Amazon SimpleDB where to start the next list of ItemNames.

Type: String

Default: None

Response Elements

Name	Description
`<Item><Name>... </Name></Item>`	Item names that match the select expression.
`<Attribute> <Name>...</Name> <Value>...</Value> </Attribute>`	The name and value of the attribute.
`NextToken`	An opaque token indicating that more than `MaxNumberOfItems` matched, the response size exceeded 1 megabyte, or the execution time exceeded 5 seconds.

Special Errors

Error	Description
`InvalidParameterValue`	Value (" + value + ") for parameter `MaxNumberOfItems` is invalid. `MaxNumberOfItems` must be between 1 and 2500.
`InvalidParameterValue`	Value (" + value + ") for parameter AttributeName is invalid. Value exceeds maximum length of 1024.
`InvalidNextToken`	The specified next token is not valid.
`InvalidNumberPredicates`	Too many predicates in the query expression.
`InvalidNumberValueTests`	Too many value tests per predicate in the query expression.
`InvalidQueryExpression`	The specified query expression syntax is not valid.
`MissingParameter`	The request must contain the parameter `DomainName`.
`NoSuchDomain`	The specified domain does not exist.
`RequestTimeout`	A timeout occurred when attempting to query domain <domain name> with query expression <query expression>. BoxUsage [<box usage value>]"
`TooManyRequestedAttributes`	Too many attributes requested.

Examples

Sample Request

https://sdb.amazonaws.com/
?Action=Select
&AWSAccessKeyId=[valid access key id]
&NextToken=[valid next token]
&SelectExpression=select%20Color%20from%20MyDomain%20where%20Color%20like%20%27Blue%25%27
&SignatureVersion=2
&SignatureMethod=HmacSHA256
&Timestamp=2007-06-25T15%3A03%3A09-07%3A00
&Version=2009-04-15
&Signature=[valid signature]

Sample Response

<SelectResponse  xmlns="http://sdb.amazonaws.com/doc/2009-04-15">
  <SelectResult>
    <Item>
      <Name>Item_03</Name>
      <Attribute><Name>Category</Name><Value>Clothes</Value></Attribute>
      <Attribute><Name>Subcategory</Name><Value>Pants</Value></Attribute>
      <Attribute><Name>Name</Name><Value>Sweatpants</Value></Attribute>
      <Attribute><Name>Color</Name><Value>Blue</Value></Attribute>
      <Attribute><Name>Color</Name><Value>Yellow</Value></Attribute>
      <Attribute><Name>Color</Name><Value>Pink</Value></Attribute>
      <Attribute><Name>Size</Name><Value>Large</Value></Attribute>
    </Item>
    <Item>
      <Name>Item_06</Name>
      <Attribute><Name>Category</Name><Value>Motorcycle Parts</Value></Attribute>
      <Attribute><Name>Subcategory</Name><Value>Bodywork</Value></Attribute>
      <Attribute><Name>Name</Name><Value>Fender Eliminator</Value></Attribute>
      <Attribute><Name>Color</Name><Value>Blue</Value></Attribute>
      <Attribute><Name>Make</Name><Value>Yamaha</Value></Attribute>
      <Attribute><Name>Model</Name><Value>R1</Value></Attribute>
    </Item>
  </SelectResult>
  <ResponseMetadata>
    <RequestId>b1e8f1f7-42e9-494c-ad09-2674e557526d</RequestId>
    <BoxUsage>0.0000219907</BoxUsage>
  </ResponseMetadata>
</SelectResponse>