Formula

Remove the column that should not define uniqueness before calling UNIQUE:

=UNIQUE(CHOOSECOLS(A2:C6, 1, 3))

This example compares columns 1 and 3 and ignores column 2.

Test setup

We entered five synthetic rows with an ID, a timestamp to ignore, and a status:

ID Ignored timestamp Status
A-100 2026-07-01 09:00 Open
A-100 2026-07-02 10:00 Open
B-200 2026-07-03 11:00 Closed
B-200 2026-07-04 12:00 Closed
C-300 2026-07-05 13:00 Open

The formula was run twice in separate, non-overlapping output areas.

Tested steps

  1. Identify the columns that should define a unique row.
  2. Use CHOOSECOLS to create an array containing only those columns.
  3. Wrap that result in UNIQUE.
  4. Leave enough empty cells for the result to expand.
  5. Repeat the formula in a separate empty area.

Both live runs returned the same three rows: A-100 / Open, B-200 / Closed, and C-300 / Open.

Why not pass the full range to UNIQUE?

UNIQUE compares the rows in the range it receives. If a changing timestamp remains in that range, otherwise identical rows are still different. CHOOSECOLS creates a smaller array first, so the ignored timestamp never participates in the comparison.

Spill-range warning

The first attempt deliberately exposed a useful failure mode: placing the second formula inside the first result’s expansion area caused #REF!. Move the formulas apart or clear the blocked cells; do not treat that error as a deduplication failure.