alamb opened a new issue, #8582: URL: https://github.com/apache/arrow-datafusion/issues/8582
### Is your feature request related to a problem or challenge? Today DataFusion supports three aggregate functions that can be "order aware": `ARRAY_AGG`, `FIRST_VALUE` and `LAST_VALUE`. This means that you can supply a `ORDER BY` clause to their argument, for example `FIRST_VALUE(x ORDER BY time)`. Today, there be only one single order specified across ALL order aware aggregate functions For example ```SQL ❯ create table t(x int, y int) as values (1, 1), (1, 2), (1, 1), (1, 4), (2, 20), (2, 10);; 0 rows in set. Query took 0.003 seconds. ❯ select x, first_value(x ORDER BY y) from t GROUP BY x; +---+------------------+ | x | FIRST_VALUE(t.x) | +---+------------------+ | 2 | 2 | | 1 | 1 | +---+------------------+ 2 rows in set. Query took 0.004 seconds. ❯ select x, first_value(x ORDER BY y), first_value(x ORDER BY y DESC) from t GROUP BY x; +---+------------------+-----------------+ | x | FIRST_VALUE(t.x) | LAST_VALUE(t.x) | +---+------------------+-----------------+ | 1 | 1 | 1 | | 2 | 2 | 2 | +---+------------------+-----------------+ 2 rows in set. Query took 0.004 seconds. ❯ select x, first_value(x ORDER BY y), first_value(x ORDER BY y DESC NULLS LAST) from t GROUP BY x; This feature is not implemented: Conflicting ordering requirements in aggregate functions is not supported ``` ### Describe the solution you'd like There are a few designs proposed here: https://github.com/apache/arrow-datafusion/pull/8558#issuecomment-1862649886 We are working on a more detailed proposal ### Describe alternatives you've considered _No response_ ### Additional context _No response_ -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
