OFFICE🔗Merge CSV
Multi-file UNION · header union
Vertically concatenates multiple CSV files (UNION). Headers are auto-merged as a union; missing columns are filled with empty strings. Column order follows the first appearance across all files.
Merge CSV: Vertical Concatenation + Header Union
This tool merges multiple CSV files into one: rows are stacked vertically, the header is the union of all files, and missing fields are left blank.
Typical scenarios: ① merge sales data split by month or week; ② merge same-template CSV reports from multiple departments; ③ merge "synonyms with different names" fields exported from different systems (specify them manually in "column mapping").
How to use: ① upload multiple CSVs (encodings and delimiters may differ — auto-detected); ② the tool shows the header union with missing fields highlighted in red; ③ choose row-level or whole-table merge (default: whole-table, one header); ④ download the merged file.
Notes: ① column mapping only unifies "same names" — "customer phone / phone / 客户电话" are distinct columns and won't auto-merge; normalize column names with another tool before merging; ② UTF-8, GBK, and GB18030 encodings are recognized, but a single file mixing multiple encodings is not supported; ③ for large files (over 10MB), merge in batches to avoid high memory usage.
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