← Back to Chapters

Append & Merge Queries

? Append & Merge Queries

✨ Quick Overview

Append and Merge are data-combining features in Power Query Editor. They allow you to unify fragmented datasets before loading them into your model.

? Key Concepts

  • Append: Think "Stacking." Adding more rows to an existing table.
  • Merge: Think "Joining." Adding more columns from a related table using a key.
  • Both happen during the Transformation phase.

➕ Append Queries (Vertical)

Used when you have multiple files with the same columns but different data (e.g., Sales Jan, Sales Feb).

? Merge Queries (Horizontal)

Used when you need to bring in related info from another table (e.g., adding Customer Names to an Order table using CustomerID).

? Use Cases

  • Append: Combining monthly CSV files into one master sales table.
  • Merge: Connecting a Product ID in your sales data to a Product Category table.
  • Data Enrichment: Merging external weather or holiday data with business metrics.

⚡ Combining Simulator

See how the table structure changes based on the operation:

Original Table (Sales)

ID Amount
101 $500
102 $750

✅ Tips & Best Practices

  • Standardize Names: Columns must have identical names for a clean Append.
  • Match Data Types: Ensure "ID" is text in both tables before merging to avoid errors.
  • Merge as New: Always use the "As New" option to keep your source tables clean for debugging.
  • The "Expand" Step: After merging, remember to click the ↔️ icon in the column header to choose which columns to keep.

? Try It Yourself

  1. Import two Sales CSVs and use Append Queries as New to stack them.
  2. Import a Customer table and Merge it with your Sales table using 'CustomerID'.
  3. Expand the merged column to show only 'Customer Name' and 'Location'.
  4. Check your Applied Steps to see the 'Source' and 'Expanded' steps.