Lookups & rollups

Lookups and rollups are derived fields that read through a relation. They keep computed context next to your records without duplicating data.

Lookups

A lookup surfaces a field from a related record. On Projects related to Clients, add a lookup Account Owner that pulls the Client’s Owner — now it shows on every Project and in Project views, always current.

Add one in one click from a relation field: choose the relation, then the field to surface.

Rollups

A rollup aggregates the related records on the other side of a relation:

Aggregation	Example
count	Open Tasks per Project
sum	Total Days across a Team Member’s Time Off
avg	Average deal size per Client
min / max	Earliest due date, largest invoice

A count rollup needs no target field; the rest aggregate a chosen number (or date) field on the related records.

Feeding formulas

Both lookups and rollups are ordinary fields that formulas can reference. The classic vacation-balance recipe:

1. On Team Members, add a rollup Days Used = sum of Days through the Time Off relation.
2. Add a formula Balance = {Allocation} - {Days Used}.

Other favorites: event budget vs actual ({Budget} - {Spent} where Spent is a sum-rollup over Expenses), and pipeline value per client (a sum-rollup over Opportunity Amount).

Traversal

Formulas work over one database at a time — there’s no {Client.Owner} traversal. Use a lookup to bring a related field in, then reference the lookup; use a rollup to aggregate, then reference the rollup.