4.3 Power Query (The Game-Changer)

Why Power Query Beats Manual Cleaning

• Time Comparison:

  • Manual: 3 hours to clean 50,000 rows

  • Power Query: 8 minutes (with refresh capability)

Advanced Transformation Techniques

1. Merging Disparate Data Sources

• Excel files + SQL databases + web APIs

• Handling inconsistent date formats across systems

2. Creating Custom Columns

= Table.AddColumn(#"Previous Step", "Profit Margin", each [Profit]/[Revenue])  

3. Parameterized Queries

• Let users select:

  • Date ranges

  • Product categories

  • Regions

Corporate Case Study:

• Unifying franchise data from 120+ locations into CEO dashboard

Assignment:

• Build self-updating competitor price tracker pulling from:

  1. Web-scraped data (mock)

  2. Internal SAP export

  3. Salesforce opportunities