Aggregation of related records --> First value only

Hello,

when a record type has a (1,n) relation, Appian supports some aggration for those related records ( 'Create Custom Record Field' --> 'AGGREGATE RELATED RECORD FIELDS').

The avaible aggregation functions seem to be dependend on the data type of the 'AGGREGATE RELATED RECORD FIELDS' - in any case, I'm looking for something like FIRST_OF (LAST_OF) so that I can get the first record field(s) of related data records (which are string based).

Maybe a small example: (Author)  <-- (Books) (an author can have many books)

Should be presented in a list

author number of books book title (first) book release year (first)
Scott Lynch 6 The Lies of Locke Lamora 2006
...

What would be a good way to achieve this?

Thank you in advance

Thomas

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  • It's not possible to use the a!relatedRecordData() function in a custom record field, but I still think you can likely get what you need. Can you share more information about your use case? If you just need to display this in a grid, you shouldn't need a custom record field. Instead, just add a!relatedRecordData() to your grid data and configure it to only return one itme.

    For instance, something like the example here would work, do to the same thing in a grid instead: docs.appian.com/.../fnc_system_relatedrecorddata.html

  • Thank you for the clarification, when building the expression within the query editor it is just fine. As of now, I cannot get to show  the result data (from an expression rule based on a query operating on a record type) in a read-only grid.

    I've built one the appian example (Acme Vehicle).

    Expression Rule (not yet figured out how to share code)

    When pasting this into a read-only grid:

    Could not display interface. Please check definition and inputs. Interface Definition: Expression evaluation error at function a!gridField [line 8]: A grid component [label="Read-only Grid"] has an invalid value for "columns". A grid column [label="Vehicleid"] has encountered an error. Expression evaluation error: Vehicle can only be indexed into using square brackets or the index function

    Probably this is another issue though - thank you.

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  • Thank you for the clarification, when building the expression within the query editor it is just fine. As of now, I cannot get to show  the result data (from an expression rule based on a query operating on a record type) in a read-only grid.

    I've built one the appian example (Acme Vehicle).

    Expression Rule (not yet figured out how to share code)

    When pasting this into a read-only grid:

    Could not display interface. Please check definition and inputs. Interface Definition: Expression evaluation error at function a!gridField [line 8]: A grid component [label="Read-only Grid"] has an invalid value for "columns". A grid column [label="Vehicleid"] has encountered an error. Expression evaluation error: Vehicle can only be indexed into using square brackets or the index function

    Probably this is another issue though - thank you.

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