| Power Query Internals |
| M Language |
Functional language used by Power Query under the hood |
| Custom Columns |
Adding new columns based on expressions or other columns |
| Conditional Logic |
If-then-else logic encoded inside Power Query steps |
| Parameters |
Reusable values that drive connection strings and filters |
| Performance and Reuse |
| Query Folding |
Translating M steps into native source queries for performance |
| Incremental Refresh |
Refreshing only the new partition rather than the whole dataset |
| Dataflows |
Reusable Power Query in the Service for shared transformation logic |
| Error Handling |
Try, otherwise, and error rows for resilient ETL pipelines |