[jira] [Closed] (FLINK-6108) Add sum(fieldName) to sum based on named POJO fields

["Greg Hogan (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/FLINK-6108?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Greg Hogan closed FLINK-6108.
-----------------------------
    Resolution: Duplicate

> Add sum(fieldName) to sum based on named POJO fields
> ----------------------------------------------------
>
>                 Key: FLINK-6108
>                 URL: https://issues.apache.org/jira/browse/FLINK-6108
>             Project: Flink
>          Issue Type: New Feature
>          Components: DataSet API
>    Affects Versions: 1.2.0
>            Reporter: Luke Hutchison
>
> Currently it is possible to do
> {code}
> dataSet.groupBy(0).sum(1)
> {code}
> but not
> {code}
> dataSet.groupBy("id").sum("count")
> {code}
> groupBy() takes named fields, but sum() does not, it only works with tuples. It would be great if sum() could take named fields too -- otherwise you have to map to tuples to make use of easy summing.
> (This would probably only work reliably with POJOs, since a new object instance would need to be constructed to take the field containing the sum.)
> Similarly, min(), max() etc. should also take named fields.



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