Add Index Column without breaking Query Folding?

[justinh]

Is it possible to add an Index Column without breaking Query Folding?
My data source is SAP HANA. 

[Payeras_BI · Accepted solution]

Hi @justinh ,

Not according to this:

[Smauro]

Just to add an explanation to this, you cannot not break query folding when adding an index, as it does need to go through each row of the table, remember where it has added each index and keep it there.

[AlexisOlson]

Theoretically, couldn't Microsoft translate adding an index into something that does fold into a native query? E.g. something like this pattern:

SELECT 
  [...]
  ROW_NUMBER(ORDER BY [...]) AS index
FROM [...]

While it's not currently implemented this way, is there anything fundamentally preventing indexing from being folded into a native query?

[justinh]

This would be very helpful to add surrogate integer keys without processing every row within Power Query.