Data Preparation & Transformation (Prepare the Data)

Unpivot Columns

"Wide table format," "Dates or months spread across column headers," "Attributes normalized into rows."

Pivot Columns

"Aggregate repeated row values into distinct column headers," "Convert tall key-value pairs into a summary grid."

Merge Queries

"Combine columns from two tables," "SQL Join," "Lookup values based on a matching key ID."

Append Queries

"Combine rows from multiple tables," "SQL UNION," "Combine monthly or regional files with identical columns."

Group By

"Reduce total row count in Power Query before loading," "Pre-aggregate granular data at a higher summary level."

Enable Query Folding

"Push processing back to the source server," "Optimize SQL source query," "Delegate transformation to database."

Disable "Enable Load"

"Staging table," "Intermediate calculation table," "Do not duplicate data in the data model memory."

Column Profile / Quality

"Identify percentage of Nulls, Errors, or Empty values," "Spot outlier values across the full dataset."

Distinct vs. Unique

"Total count of non-duplicate values" (Distinct) vs. "Values that appear exactly once" (Unique).