# Data Append Merger

Vertically append and merge multiple data tables with intelligent column matching

> Canonical page: https://elysiatools.com/en/tools/data-append-merger

- **Category:** Data Processing

- **Keywords:** data, merge, append, combine, table, csv, vertical, concatenate, data append merger

## Overview

The Data Append Merger is a powerful utility designed to vertically stack multiple data tables into a single, unified dataset using intelligent column matching to ensure data integrity.

## Inputs

- **Input Data Tables** (textarea): Enter multiple data tables separated by empty lines. Each table should have consistent column structure.
- **Delimiter** (select)
- **First Row Contains Headers** (checkbox)
- **Column Alignment Mode** (select)
- **Fill Missing Values** (checkbox)
- **Output Separator** (select)
- **Include Headers in Output** (checkbox)
- **Duplicate Header Prefix** (text): Prefix to add to duplicate header names (e.g., "Table1_")

## When to use

- When you need to combine multiple CSV or text-based reports that share the same structure.
- When you have fragmented data files that need to be consolidated into one master table for analysis.
- When you need to align columns across different datasets that may have slightly varying header names or positions.

## How it works

- Paste your data tables into the input area, ensuring they are separated by empty lines.
- Select your preferred alignment mode—Smart, By Position, or By Column Name—to dictate how columns are matched.
- Configure output settings such as header inclusion and missing value handling.
- Click to process and generate your consolidated, vertically merged dataset.

## Use cases

- Consolidating monthly sales reports from different regional branches into a single annual master file.
- Merging survey results collected from multiple sources into one comprehensive dataset for statistical analysis.
- Combining fragmented log files into a single chronological table for easier troubleshooting.

## Frequently asked questions

### What does 'Smart' alignment mode do?

Smart mode combines both column position and header name matching to intelligently align data even if column orders differ slightly between files.

### How are missing values handled?

If enabled, the tool will automatically fill missing cells with empty values to maintain the structure of the resulting table.

### Can I merge files with different delimiters?

Yes, the tool includes an auto-detect feature for input delimiters to help process files with varying formats.

### What happens if header names are duplicated?

You can specify a custom prefix in the 'Duplicate Header Prefix' field to distinguish between columns that share the same name.

### Is there a limit to how many tables I can merge?

You can merge as many tables as your browser's memory allows, provided they are separated by empty lines in the input field.

## Related tools

- [Column Calculator](https://elysiatools.com/en/tools/column-calculator): Perform calculations on columns and add new rows
- [Column Reorder](https://elysiatools.com/en/tools/column-reorder): Reorder table columns without changing the data rows
- [Row Calculator](https://elysiatools.com/en/tools/row-calculator): Perform calculations on each row and add new columns
- [Column Remover](https://elysiatools.com/en/tools/column-remover): Remove specified columns from table data
- [Data Column Extractor](https://elysiatools.com/en/tools/data-column-extractor): Extract specific columns from tabular data with support for various formats and flexible column selection
- [Feature Scaler](https://elysiatools.com/en/tools/feature-scaler): Scale and normalize features using various methods for machine learning preprocessing and data standardization
- [CSV Validator](https://elysiatools.com/en/tools/csv-validator): Validate CSV structure, detect malformed rows, unbalanced quotes and column mismatches
- [CSV Column Reorderer](https://elysiatools.com/en/tools/csv-column-reorder): Reorder, remove, and rearrange CSV columns with customizable column positions

## Samples

- [CSV Samples](https://elysiatools.com/en/samples/csv-samples): Sample CSV files with various data types, sizes, and complexity levels
- [Python Samples](https://elysiatools.com/en/samples/python): Essential Python code examples and Hello World demonstrations
- [Windows String Processing - C# Samples](https://elysiatools.com/en/samples/windows-string-processing-csharp): Comprehensive C# string processing examples for Windows platform including string manipulation, splitting, joining, regex operations, and text analysis
- [WebRTC Real-Time Communication Samples](https://elysiatools.com/en/samples/webrtc-samples): Comprehensive WebRTC samples for peer-to-peer audio/video communication, data channels, screen sharing, and signaling server implementation

## Related content

- [Tabular Data Cleanup, Shaping, and Normalization](https://elysiatools.com/en/hubs/tabular-data-cleanup-and-normalization): Take messy tabular data to analysis-ready — merge source tables into one, strip the byte-order marks that break column matching, keep only the columns you need, fix spellings and formats, handle outliers by policy instead of panic, scale or standardize the numbers, and finish with range limits and a crosstab summary.