Gigasheet makes it easy to combine or merge many files, from CSVs or Excel workbooks to JSON. Simply select two or more files in your library by clicking the small checkbox to the left of the file name. Use the Combine button in the Library to merge two or more files of the same structure. For example, if you have 28 daily logs from the same server, you can merge them into a single sheet using the Combine feature.
Note: all files must have the same columns, column order, and column data types.
See this video for more information on Combining Files in Gigasheet.