What transformations commonly break query folding?

< 1 min read

Transformations that commonly break query folding include adding custom columns using complex M logic.
In one project, using a row-level conditional column early in Power Query stopped folding.
Index column creation often breaks folding for many data sources.
Merging with non-foldable sources like Excel or CSV files also breaks it.
Using certain text transformations or unsupported functions can stop native query generation.
Reordering steps incorrectly may prevent filters from being pushed down.
Removing duplicates or grouping after a non-foldable step also impacts folding.
We always checked “View Native Query” to ensure folding was maintained.

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