--- category: [Administration & Integrations, Administration & Integrations/Custom Integrations & Apps, Platform and Product Extensions, Platform and Product Extensions/Workday Extend, Platform and Product Extensions/Integration] keyword: [Extend, Orchestration Builder, Orchestrate, Orchestration] nav: wcp_docs parent_url: /wcp_docs/ title: Add Aggregations layout: subsection --- ### Prerequisites Create an orchestration containing a Loop, Batch Loop, or Join Loop step. ### Context Aggregation is the process of condensing data items into a single output item by applying a function called an aggregation strategy to each iteration of a loop. In Orchestration Builder, you can apply an aggregation strategy to a Loop, Batch Loop, or Join Loop step. You can include any data item that's in scope for the loop. ### Steps 1. To add an aggregation, click the 3 dots menu on the relevant loop step and select Add Aggregation. 2. Provide a Reference Name for the step. 3. Click Add Output. 4. Provide a Name for the output and from the Strategy drop-down list, select the aggregation strategy you want to use with it. 5. Click on the output to open its configuration panel. The information required here depends on your choice of aggregation strategy. All aggregation strategies enable you to specify a Condition. Orchestration Builder only aggregates items for which the condition evaluates to `true`. To throw an exception when no input items meet your selection criteria, select the Fail When No Inputs check box. This table summarizes the purpose of the available strategies and their configuration options:

Aggregation Strategy	Description
XML Fold	Aggregates XML fragments and outputs them as a single XML document. In the Select XML Fragment field, use Expression Builder to define an XML fragment for inclusion in the aggregation during a loop iteration. To add an XML declaration to the output document, select the Include XML Declaration checkbox. Enter a Header and Footer for the output document, and specify a Line Separator, if required. On the Namespaces tab, add namespaces to the output document, if required. On the Advanced tab, define a specific Xpath node for inclusion in the output, if required.
CSV Fold	Aggregates CSV rows and outputs them as a single CSV document. In the String List field, use Expression Builder to define a CSV row for inclusion in the aggregation during a loop iteration. Alternatively, from the Format drop-down list, select a custom CSV format. You can create these using CSV Formats in your application's Settings.
JSON Fold	Aggregates JSON fragments and outputs them as a single JSON array. In the Select JSON Fragment field, use Expression Builder to define a JSON fragment for inclusion in the aggregation during a loop iteration.
Text Fold	Aggregates text fragments and outputs them as a single text document. In the Select Text field, use Expression Builder to define a text fragment for inclusion in the aggregation during a loop iteration. Select the Content Type of the specified text: application/json application/octet-stream application/x-www-form-urlencoded application/xml text/csv text/html text/plain text/xml Specify a Line Separator for the output document. Define a Header and Footer for the output document, if required.
Number List	Aggregates numbers and outputs them as a list of type `NumberList`. In the Select Number field, use Expression Builder to define a number for inclusion in the aggregation during a loop iteration.
String List	Aggregates strings and outputs them as a list of type `StringList`. In the Select String field, use Expression Builder to define a string for inclusion in the aggregation during a loop iteration.
Boolean List	Aggregates boolean values and outputs them as a list of type `BooleanList`. In the Select Boolean field, use Expression Builder to define a boolean value for inclusion in the aggregation during a loop iteration.
Maximum	Aggregates numbers and outputs the maximum value among them. In the Select Number field, use Expression Builder to define a number for inclusion in the aggregation during a loop iteration.
Minimum	Aggregates numbers and outputs the minimum value among them. In the Select Number field, use Expression Builder to define a number for inclusion in the aggregation during a loop iteration.
Sum	Aggregates numbers and outputs the sum of their values. In the Select Number field, use Expression Builder to define a number for inclusion in the aggregation during a loop iteration.
Count	Outputs a count of the aggregated items.
Date List	Aggregates Dates and outputs them as a list of type `DateList`. In the Select Date field, use Expression Builder to define a date for inclusion in the aggregation during a loop iteration.
Local Date Time List	Aggregates Local Date Times and outputs them as a list of type `LocalDateTimeList`. In the Select Local Date Time field, use Expression Builder to define a Local Date Time for inclusion in the aggregation during a loop iteration.
Local Time List	Aggregates Local Times and outputs them as a list of type `LocalTimeList`. In the Select Local Time field, use Expression Builder to define a Local Time for inclusion in the aggregation during a loop iteration.
Zoned Date Time List	Aggregates Zoned Date Times and outputs them as a list of type `ZonedDateTimeList`. In the Select Zoned Date Times field, use Expression Builder to define a Zoned Date Time for inclusion in the aggregation during a loop iteration.
Zip Archive	Aggregates data and outputs it as a Zip archive. In the Select Data field, use Expression Builder to define data for inclusion in the aggregation during a loop iteration. In the Path field, use Expression Builder to define the path within the Zip archive for the current data item.
String Map	Aggregates key and String value items and outputs them as a map of type `StringMap`. In the Select String Key and Select String Value fields, use Expression Builder to define the key and value of a map item for inclusion in the aggregation during a loop iteration.
Number Map	Aggregates key and Number value items and outputs them as a map of type `NumberMap`. In the Select String Key and Select Number Value fields, use Expression Builder to define the key and value of a map item for inclusion in the aggregation during a loop iteration.
Boolean Map	Aggregates key and Boolean value items and outputs them as a map of type `BooleanMap`. In the Select String Key and Select Boolean Value fields, use Expression Builder to define the key and value of a map item for inclusion in the aggregation during a loop iteration.
Date Map	Aggregates key and Date value items and outputs them as a map of type `DateMap`. In the Select String Key and Select Date Value fields, use Expression Builder to define the key and value of a map item for inclusion in the aggregation during a loop iteration.
Local Date Time Map	Aggregates key and Local Date Time value items and outputs them as a map of type `LocalDateTimeMap`. In the Select String Key and Select Local Date Time Value fields, use Expression Builder to define the key and value of a map item for inclusion in the aggregation during a loop iteration.
Local Time Map	Aggregates key and Local Time value items and outputs them as a map of type `LocalTimeMap`. In the Select String Key and Select Local Time Value fields, use Expression Builder to define the key and value of a map item for inclusion in the aggregation during a loop iteration.
Zoned Date Time Map	Aggregates key and Zoned Date Time value items and outputs them as a map of type `ZonedDateTimeMap`. In the Select String Key and Select Zoned Date Time Value fields, use Expression Builder to define the key and value of a map item for inclusion in the aggregation during a loop iteration.
Custom Fold	Aggregates and outputs data items of any of these types, which you can select from the Output Type drop-down list: `String` `Boolean` `Number` `Text` `Data` `StringList` `BooleanList` `NumberList` `JSON` `XML` `CSV` `Date` `LocalTime` `LocalDateTime` `ZonedDateTime` In the Initial Value field, use Expression Builder to define the first value for inclusion in the aggregation. Example: the third value in a `NumberList`. In the Next Value field, use Expression Builder to define how the aggregation proceeds in subsequent iterations. Example: only include even numbered values.

6. Add and configure additional outputs, as required.