DAX to M

Hi M_SBS_6 ,

Your DAX formula calculates a value based on conditions related to the year of the appdate and the count of rows that meet certain criteria. To achieve a similar outcome in M within Power Query, we'll follow a step-by-step approach. Please note that M operates differently from DAX, and some logic may need to be adjusted to fit the procedural nature of M.
You can try this M function:

let
    Source = YourSourceTable, // Replace YourSourceTable with your actual source step
    _max_year = Date.Year(List.Max(Source[appdate])),
    _min_year = _max_year - 3,
    // Add a custom column to perform the row filtering and counting
    AddCustom = Table.AddColumn(Source, "Custom", each let
        _cur_appname = [appname],
        _filtered = Table.SelectRows(Source, each [appname] = _cur_appname 
            and Date.Year([appdate]) >= _min_year 
            and Date.Year([appdate]) < _max_year),
        _count = Table.RowCount(_filtered)
    in
        if Date.Year([appdate]) = _max_year and _count = 0 then "Yes" else null)
in
    AddCustom

This code is a starting point and may need adjustments based on your specific requirements and data structure. Remember, the M language is case-sensitive and procedural, so the order of operations is crucial.

Best Regards,
Dino Tao
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