Merging Two Messy CSVs: The Key Problems Excel Formulas Hide From You

Merging two messy CSV files using Excel formulas often leads to significant data disasters. This process incorrectly assumes that IDs match perfectly, columns share identical meanings, and rows remain unique. Professionals reconciling chat logs, server logs, and marketplace exports identify these merges as primary failure points. A common issue is that the designated key is not a true key, as one file may use id while another uses customer_id, causing critical errors during the data reconciliation process.