Merge multiple Excel files into a single multi-sheet file with summary page

Overview

This workflow automates the process of merging multiple .xlsx files from a designated folder into a single, well-organized Excel workbook. Each input file is converted into its own sheet within the output file. Additionally, a summary sheet is generated at the beginning, providing a convenient overview of all merged files, including their original names and the number of records in each.

This is particularly useful for consolidating reports, combining data from different sources, or archiving multiple spreadsheets into one manageable file.

How It Works

The workflow follows these key steps:

1. Trigger: The process begins when you manually execute the workflow.
2. Read Files: It reads all files ending with the .xlsx extension from the /n8n_files/ directory (ensure your volume is mapped correctly).
3. Process Each File: The workflow iterates through each file one by one. For each file, it extracts the data from the first sheet.
4. Collect and Clean Data: A custom code node gathers the data from all files. It cleans the data by removing any completely empty rows and prepares it for the final Excel generation. The original filename is used to name the new sheet.
5. Generate Multi-Sheet Excel: The core logic resides in a code node that uses the xlsx library. It creates a new Excel workbook in memory, adds a sheet for each processed file, and populates it with the corresponding data. It also creates a "Summary" sheet that lists all the source files and their record counts.
6. Save the Result: The final workbook is saved as a new .xlsx file in the /n8n_files/output/ directory with a timestamped filename (e.g., 合并文件_20250908T123000.xlsx).

Setup & Prerequisites

To use this workflow, you need to configure your n8n instance to allow and use the external xlsx npm module.

1. Place Your Files: Put all the Excel files you want to merge into the folder that is mapped to /n8n_files/ in your n8n container.
2. Enable External Module:
   • Set the following environment variable for your n8n service in your docker-compose.yml file:

     environment:
       - NODE_FUNCTION_ALLOW_EXTERNAL=xlsx
     

3. Install the Module: You must build a custom Docker image for n8n that includes the xlsx library.
   • In the same directory as your docker-compose.yml, create a file named Dockerfile.
   • Add the following content to the Dockerfile:

     FROM n8nio/n8n:latest
     USER root
     RUN npm install xlsx
     USER node
     

   • In your docker-compose.yml, replace the image: n8nio/n8n... line with build: . for the n8n service.
   • Rebuild and restart your n8n container using docker-compose up --build -d.

Nodes Used

• Manual Trigger: To start the workflow.
• Read Write File: To read source files and save the final output file.
• Split In Batches: To process files one by one.
• Extract From File: To read the data from each .xlsx file.
• Code: For custom JavaScript logic to process data and generate the final multi-sheet Excel file using the xlsx library.