CSV Coalesce Columns

CSV coalesce columns

Build one column from the first non-empty value across several columns, read in the priority order you list them — the SQL COALESCE idea applied to columns instead of expressions. It's the fastest way to fold mobile/office/home into a single phone, or a web price with a list-price fallback, without writing a spreadsheet formula. Optionally drop the source columns, choose where the new column lands, and set a fallback for rows where every source is empty. Runs entirely in your browser; nothing is uploaded.

Worked example

Input — three phone columns, filled in unevenly:

name,mobile,office,home
Ann,555-1,555-2,555-3
Bob,,555-4,555-5
Cleo,,,555-6

Source columns mobile,office,home, new column name phone → output:

name,mobile,office,home,phone
Ann,555-1,555-2,555-3,555-1
Bob,,555-4,555-5,555-4
Cleo,,,555-6,555-6

Ann keeps her mobile (first in the priority list), Bob falls through to the office number, Cleo all the way to home. Turn on Drop the source columns and set the position to where the first source column was to get the tidy version instead:

name,phone
Ann,555-1
Bob,555-4
Cleo,555-6

Options

• Source columns — comma-separated, highest priority first: header names (mobile,office,home) or 1-based indices (2,3,4). A purely numeric token is always read as an index, so a column literally named 2 must be addressed by its position.
• New column name — blank uses coalesced. It must not clash with a column you keep.
• Put the new column — at the end, at the start, or where the first source column sat.
• Fallback — written when every source is empty for that row (N/A, unknown, …). Blank leaves the cell empty.
• Drop the source columns — removes them after merging, so only the new column remains.
• Treat whitespace-only cells as empty — on by default, so a stray space is skipped rather than winning.
• Extra placeholders that count as empty — comma-separated tokens such as NULL,NA,N/A,-, matched case-insensitively against the trimmed cell.
• First row is a header — keeps and rewrites the header row, and lets you name columns instead of counting them.
• Delimiter — comma, tab, semicolon, pipe, or any single character.

Limits & edge cases

• Only emptiness decides the winner — no type checks, no 0/false special case. A cell containing 0 is a real value and wins.
• Placeholders like NULL or N/A are ordinary text unless you list them under Extra placeholders that count as empty.
• Rows shorter than the widest row are padded with empty cells, so a missing trailing column simply falls through to the next source.
• Listing the same column twice, naming a column that isn't in the header, or using an index past the last column is an error rather than a silent skip.
• The new column's name must not collide with a column you keep — rename it, or drop the sources.
• Values are copied verbatim (quotes, inner commas, unicode); the tool never reformats or trims the value it picks.

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