Combine Data from Multiple Worksheets

1. The Crucial First Step: Excel Tables

Just like when we combined separate files, Power Query works best when your data is structured. Before we can append data from multiple sheets, we must first ensure the data on each sheet is formatted as a named Excel Table.

This is not an optional step. Power Query needs these formal table structures to identify and process the data ranges on each sheet automatically.

The process is simple:

1. Click anywhere within your data range on a worksheet.
2. Go to the Insert tab and click Table, or use the shortcut Ctrl + T.
3. Ensure Excel has correctly identified your data range and that the "My table has headers" box is checked (if applicable).
4. After creating the table, go to the Table Design tab, and in the Table Name box on the far left, give your table a descriptive name (e.g., Jan_Sales, Q1_Incidents). This is a best practice that makes your queries much easier to manage.

2. Method 1: The Dynamic Approach with Excel.CurrentWorkbook()

Our first method is the most efficient and scalable. It uses a single Power Query function to find all the tables in your current workbook and combine them automatically. This method is particularly powerful because it will automatically include any new worksheets (that you convert to tables) when you refresh it later.

Let's watch a video that walks through this entire process.

Understanding the Recursion Problem

The "recursion" issue highlighted at the end of the video is a common pitfall. To make it crystal clear, let's review the excellent explanation from the Trump Excel website.

3. Method 2: The Explicit Approach with "Append Queries"

There is another way to combine worksheets, which is more manual but gives you more explicit control. This method involves:

1. Creating a separate query for each worksheet table, loading them as "connection only."
2. Using the Append Queries command to stack these connections into a new, combined query.

This method is useful if you need to perform different cleaning steps on each table before combining them, or if you want to add identifying information (like a "Region" or "Month" column) to each table first.

Let's watch a video demonstrating this approach.

While this method works perfectly well, for most standard consolidation tasks where the sheet structures are identical, the Excel.CurrentWorkbook() method is faster and more scalable.

4. Your Turn: Consolidate Quarterly Incident Reports

Now, let's apply what you've learned to a scenario from your cybersecurity background. You have an Excel file where incident data is logged on separate worksheets for each quarter. Your task is to create a consolidated master incident log.

We will use the more dynamic Method 1 (Excel.CurrentWorkbook()) for this exercise.

1. Create Your Sample Data:

• Open a new, blank Excel workbook and save it as Master Incident Log.xlsx.
• Rename Sheet1 to Q1_Incidents. Create two more sheets named Q2_Incidents and Q3_Incidents.
• On the Q1_Incidents sheet, enter the following data:

• Copy this table and paste it onto the Q2_Incidents and Q3_Incidents sheets. Change the dates and Incident IDs slightly for each quarter to simulate new data.

2. Format as Excel Tables:

• For each of the three worksheets (Q1, Q2, Q3):
  • Click inside the data.
  • Press Ctrl + T.
  • In the Table Design tab, name the tables Q1_Data, Q2_Data, and Q3_Data respectively.

3. Combine with Power Query:

• Go to Data > Get Data > From Other Sources > Blank Query.
• In the Power Query Editor's formula bar, type =Excel.CurrentWorkbook() and press Enter.
• You will see a list of the three tables you created.
• Click the expand icon (the two arrows) on the Content column header. Uncheck "Use original column name as prefix" and click OK. Your data is now combined!

4. Prevent the Recursion Error:

• Before we load the data, we must apply the filter to prevent future errors.
• In the Applied Steps pane on the right, click on the very first step, named Source.
• The query will now show the list of tables again. Let's rename our query first. In the Query Settings pane, change the Name from Query1 to Master_Log.
• Now, click the filter arrow on the Name column header. Go to Text Filters > Does Not Equal.
• In the dialog box, type Master_Log (the name of your query). Click OK.
• Click on the last applied step in the list (likely "Changed Type") to see your final combined data again.

5. Load and Test:

• Click Close & Load in the top-left corner. A new sheet will be created with your Master_Log table.
• Now, test the automation:
  • Create a new sheet named Q4_Incidents.
  • Add some new incident data and format it as a table named Q4_Data.
  • Go back to the Master_Log sheet, right-click inside your combined table, and select Refresh.
  • The Q4 data should appear instantly at the bottom of the table.

You have successfully built an automated system for consolidating data from multiple worksheets!

Conclusion

Great work! You've just added another essential Power Query skill to your toolkit. Consolidating data is a fundamental task for any MIS role, and knowing how to automate it sets you apart.

Key Takeaways:

• Excel Tables are essential. Power Query needs data to be in a named Excel Table to append it from multiple sheets.
• The =Excel.CurrentWorkbook() function is a fast, dynamic way to combine all tables within a workbook.
• When using this method, you must filter out the final query's name from the source step to prevent recursion errors that duplicate your data upon refresh.
• The Append Queries command offers a more manual alternative, useful for creating "connection-only" queries or when you need more granular control before combining.

In our next lesson, we'll dive deeper into the Power Query Editor itself. Now that you know how to bring data in from multiple files and multiple sheets, we'll focus on applying basic data transformations like filtering rows, removing columns, and changing data types to clean and prepare your data for analysis.