make-series operator not supported inside partition by, even though it should be

@Kasper

The issue you’re encountering happens because the make-series operator internally uses a join, and currently, the partition operator does not support subqueries containing operators like join. This is why you see the error:

Operator 'partition-by': 'join' cannot be used inside the subquery

While the documentation indicates that subqueries inside partition can contain various operators, there are some known limitations, and operators that rely on join are one of them.

To achieve your goal of creating time series per State, you can avoid partition altogether and instead use the by clause directly within make-series, like this:

StormEvents
| make-series DamageProperty=max(DamageProperty) default=double(null) on StartTime step 1m by State

This approach groups the time series by State and should give you the results you want without running into the partition limitation.

Please refer to MS Q&A thread - https://learn.microsoft.com/en-us/answers/questions/1156900/partition-use-subquery-inside-partition-subquery-w addressing similar issue.

For additional information, please refer: https://learn.microsoft.com/en-us/azure/stream-analytics/stream-analytics-parallelization#example-of-scenarios-that-aren%27t%5C*-embarrassingly-parallel

I hope this information helps. Please do let us know if you have any further queries.

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