Merge CSV Files
Combine multiple CSV files into one table
Merge CSV Files — what it does
Stack several CSV files into one table, with an option to add a column recording which file each row came from. Unlike a join, this appends rows rather than widening them, which is what you need when a report arrives split by month, by branch or by export batch.
When this tool helps
- Combining twelve monthly exports into a single file before analysing a full year.
- Merging per-branch or per-region reports that share the same column layout.
- Consolidating results collected by several people into one dataset for review.
How to use it
- Select all the CSV files to combine.
- Turn on the source filename column if you need provenance.
- Process the merge.
- Download the combined CSV.
Accuracy, limits, and good practice
- Files should share the same headers. Mismatched column names produce a table with gaps where a file did not supply that field.
- The source filename column is worth keeping — once rows are stacked, there is otherwise no way to tell where a given row came from.
- Check for duplicate rows afterwards, especially if the exports overlapped in date range; the deduplicator will clean them by key.
Frequently asked questions
Is the header repeated for each file?
No. One header row is written and the data rows from every file follow beneath it.
Does file selection order matter?
It sets the row order in the output. Sort afterwards with the CSV sorter if you need a specific sequence.
What if one file uses semicolons?
Convert it first with the delimiter converter so all inputs parse consistently before merging.
Related tools on this site
- CSV Date Normalizer — Convert one CSV date column to a consistent format
- CSV to Markdown Table — Convert a CSV file into a Markdown table
- Excel to CSV — Export one worksheet or every worksheet as CSV files
Everything above runs inside this page. Merge CSV Files needs no account, no upload, and no server round trip — close the tab and nothing is left behind.
合併 CSV 檔案能做什麼
把多份 CSV 疊成同一張表，並可選擇加上一欄記錄每列來自哪個檔案。與關聯合併不同，這是往下追加資料列而非往右加寬欄位，正好用在報表依月份、依分店或依批次分開匯出的情況。
什麼時候用得上
- 把十二份月報匯出檔合成一份，再進行全年分析。
- 合併欄位結構相同的各分店或各地區報表。
- 把多人各自收集的結果整合成單一資料集以供檢視。
使用步驟
- 選取所有要合併的 CSV 檔案。
- 如需追溯來源，開啟來源檔名欄位。
- 執行合併。
- 下載合併後的 CSV。
精確度、限制與實務建議
- 各檔案應使用相同標題。欄位名稱不一致時，缺少該欄的檔案會在表中留下空格。
- 來源檔名欄很值得保留，資料一旦疊在一起，否則就無從得知某一列出自哪份檔案。
- 合併後請檢查重複列，尤其匯出區間有重疊時；可用去重工具依鍵值清理。
常見問題
每個檔案的標題都會重複出現嗎？
不會。只會寫入一列標題，所有檔案的資料列接在其下方。
選檔順序有差嗎？
會決定輸出的列順序。若需要特定順序，可事後用 CSV 排序工具處理。
如果其中一份用分號分隔呢？
請先用分隔符轉換工具統一格式，確保所有輸入都能一致解析後再合併。
本站相關工具
- CSV 日期格式統一 — 將指定日期欄位轉換成一致格式
- CSV 轉 Markdown 表格 — 將 CSV 檔案轉成 Markdown 表格
- Excel 轉 CSV — 將指定工作表或全部工作表匯出為 CSV
以上步驟全部在這個頁面內完成，合併 CSV 檔案 不需要註冊、不上傳檔案、也不經過伺服器，關閉分頁後不會留下任何資料。