The Problem: Duplicate Values in Lookup Fields

Lookup fields in Airtable are great for surfacing related information, but they can show the same linked value multiple times. Users often expect a simple "show unique" toggle, but it doesn't exist (yet). This guide explains how to deduplicate values in practice and what to do if you need to keep linkability.

Key Concepts

Lookup fields render values pulled through a linked relationship and intentionally allow duplicates.
Rollup fields can apply functions like ARRAYUNIQUE() to aggregate and deduplicate—returning text, not links.
Formulas can transform lookup arrays but cannot turn text back into clickable linked records.

Implication: If you only need a clean text list, use Rollup/Formula. If you need clickable unique links, use a data or automation workaround.

Option A — Rollup with ARRAYUNIQUE (Text Output)

If text is enough, use a Rollup that points to a field you want to dedupe and apply ARRAYUNIQUE(values).

ARRAYUNIQUE(values)

To control separators, wrap with ARRAYJOIN:

ARRAYJOIN(ARRAYUNIQUE(values), ", ")

This yields a deduplicated, readable list—but it's no longer clickable links.

Option B — Helper Field + Rollup (Reliable Deduping)

Some users notice ARRAYUNIQUE() behaves more reliably when used on plain text. Create a small helper field in the linked table and roll that up.

Example (Recipes → Ingredients → Type):

In Ingredients, add a Formula {Type Name} that equals the name of the linked {Type} (or a Lookup to {Type}.{Name} that resolves to text).
In Recipes, Rollup the {Type Name} with:

ARRAYJOIN(ARRAYUNIQUE(values), ", ")

Result: "Dairy, Bread, Vegetable, Meat" instead of repeated entries.

Option C — Keep Links Unique (Workarounds)

If you must keep them as clickable links, you need to curate a unique set in a linked-record field. Two common approaches:

1) Automation (Make/Zapier or Airtable automation)

Trigger on change to the source links.
Compute the unique set (use a script step or a Make/Zapier "remove duplicates" action).
Update a dedicated linked-record field with the unique record IDs.

Pros: stays in Airtable; links remain clickable.
Cons: needs an automation and a second field.

2) Junction Table for Unique Membership

Create a join table (e.g., Recipe ↔ Type) where each record is a unique pair.
Link your main record to this junction, and Rollup/Lookup via the junction.

Pros: fully normalized; no duplicates by design.
Cons: extra table and relationships; slightly more setup.

Quick Reference

Goal	Recommended approach
Clean readable list	Rollup + `ARRAYUNIQUE(values)` ± `ARRAYJOIN`
Unique but clickable links	Automation that writes a deduped set into a linked field
Strict uniqueness by design	Junction table (unique pairs)

Example Formulas and Patterns

Deduping a lookup into a comma-separated list:

ARRAYJOIN(ARRAYUNIQUE(values), ", ")

Building a helper key (in the linked table) to roll up confidently as text:

CONCATENATE(Name)

Then roll up {Helper Name} with ARRAYUNIQUE.

Opinionated Take

An "Only display unique linked records" toggle in Lookup settings would fit many real-world cases and appears frequently in community requests. Until then, the combination of helper text + rollup or a small automation covers most needs.

Airtable Lookups: How to Remove Duplicates (And Keep Your Links)