Pattern to incrementally amass data with Dataflow Gen2

[Romain-Ch]

Hi,
I encouter a problem following this tutorial : Pattern to incrementally amass data with Dateflow Gen2 of microsoft learn.

It is said : This assumes that orders are added to the source in ascending order of OrderID. If this isn't the case, you can use a different column to filter the data. For example, you can use the OrderDate column to filter the data.

I tried doing it with OrderDate, but when i want to ddo the statistics and maximum it is in grey and i can't click on it.

My OrderDate is in Date/Time format.

Thank you.

[Romain-Ch]

Hello,

Thank you for your answer.

My initial OrderDate column is of type Date/Time and when i drill down into it i have this : 

I have only one column which is selected but maximum is still in grey.

[v-saisrao-msft · Accepted solution]

Hi  @Romain-Ch,
Thank you for reaching out to the Microsoft Fabric Forum Community. 

Thank you @nilendraFabric, for your valuable insights.

Thank you for providing the detailed context and screenshot. Based on your description and the behavior you're observing in Power Query for Dataflow Gen2, it seems that the "Maximum" option is greyed out because the column you're working with has been drilled down into a list. In Power Query, the Statistics operations like Maximum, Minimum, etc., are only available when working with a table column, not a standalone list. 

• Recommended Solution: Instead of drilling down into the OrderDate column (which creates a list and disables the "Maximum" option), stay in the table view and use a custom M step to calculate the maximum. In the formula bar, enter: 

             = List.Max(PreviousStepName[OrderDate]) 

          Replace PreviousStepName with the actual name of your previous step. This approach directly                returns the maximum date from the column and avoids the limitations caused by working with a            list. 

• If you prefer not to use custom M code, you can calculate the maximum date using the Group By feature. In the table view, select the OrderDate column, then go to Transform > Group By. In the dialog, leave the Group By field empty to apply the operation globally, name the new column MaxOrderDate, choose the operation Max, and set the column to OrderDate. Click OK to return a single-row table containing the maximum date from the column. 

If this post helps, then please give us ‘Kudos’ and consider Accept it as a solution to help the other members find it more quickly. 

Thank you. 

[Romain-Ch]

Hello, 

I used the M step and it is working !!

But i used "List.Max(PreviousStepName[OrderDate])" and not "= List.Max(PreviousStepName[OrderDate])"

Thank you for helping me and finding the answer.

[nilendraFabric]

Please make sure

ordeedatw column is correctly identified as Date/Time in the dataflow.
• There are no transformations or errors in earlier steps that might affect its usability.

Before applying the “Maximum” operation, you might need to drill down to ensure you’re working with a single column. To do this:
1. Right-click on the `OrderDate` column and select Drill Down.
2. Then, navigate to Transform > Statistics > Maximum.