Intermediate level · Module 1: Power Query for Data Preparation · Lesson 2 of 3
Reshaping and Combining Data
Unpivot wide tables, append monthly files and merge related tables.
In this lesson you will
- Unpivot cross-tab data into a tidy table
- Append and merge queries
Key concepts
unpivotappendmerge (join)join kinds
The lesson
Many reports arrive wide, with one column per month. Unpivot turns them into a tidy table with month and value columns, ready for PivotTables and models.
Append stacks tables with the same columns, such as monthly files. Merge joins tables on a key, like a lookup — for example adding the branch region from a branch table.
Choose the join kind deliberately: left outer keeps every row of the first table; inner keeps only matches. Check row counts after merging.
Step by step
- Unpivot a wide budget table.
- Append two monthly tables.
- Merge the branch table to add regions.
- Check row counts before and after.
Practice activity
Reshape and combine the practical activity's monthly data with the branch table.
Expected result: A tidy combined table with correct row counts.
Check your understanding
-
What does unpivoting do?
Show answer
Turns columns such as months into rows of a single column.
-
What is the difference between append and merge?
Show answer
Append stacks rows; merge joins tables on a key.
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