Need Help - New column with earliest date for each ID

[DRing]

I need to a way to create the Assigned Date column in Power Query. The goal of the coulmn is to assign the earlist Sale Date for each record with the same Territory_ID. One caveat is that the Assigned Date should be the Sale Date for any records where Territory_ID is null.

Can anyone help?

[DRing]

Also, I'm unable to save these changes as my table is using DirectQuery. Is there a way around this?

[Vijay_A_Verma]

Insert this step as next step where #"Changed Type" should be replaced with your previous step in both the places

= Table.AddColumn(#"Changed Type", "Custom", (x)=> if x[Territory_ID]=null then x[Sale Date] else List.Min(Table.SelectRows(#"Changed Type"[[Territory_ID],[Sale Date]], each ([Territory_ID] = x[Territory_ID]))[Sale Date]))

[DRing]

Thank you for this. Would it be possible to introdude Status as a criteria so that

if Status = New than Assigned Date = Sales Date

If Status = Existing than Assigned Date = EARLIEST Sale Date for records with same Territory_ID?