> ## Documentation Index > Fetch the complete documentation index at: https://zite.com/llms.txt > Use this file to discover all available pages before exploring further. # Summarize linked records with a rollup field > Automatically summarize values from linked records, such as totals, averages, and counts. ## How it works A rollup field **summarizes values from linked records**. When the linked data changes, the rollup updates automatically. To add a rollup field, you first need a [link to table field](/help/database/configure-database/link-records). For example, you might have a Customers table linked to Orders. A rollup can show each customer's total order value, number of orders, or latest order date instead of calculating those yourself. To show a field from a linked record without summarizing it, use a [lookup field](/help/database/configure-database/lookup-field). Use a rollup when you want a total, count, or other summary across the linked records. ### Common use cases * **Sales CRM:** Show total deal value or the number of open deals on each company * **Project Management:** Count tasks on a project, or show the earliest due date * **Customer Support:** Count open tickets for each customer * **Quotes and Invoices:** Sum line-item amounts on a quote or invoice * **Reviews:** Average ratings from related review records ## Rollup fields If you haven't already, add a [Link to table field](/help/database/configure-database/link-records) so your rollup has related records to summarize. Click `+ Add field` and choose `Rollup`. You can also ask Zite in the chat box. For example, "Add a rollup that totals Order amount for each customer." Name the field, choose the linked-record field, pick the field to summarize, and choose how to summarize it. Then click `Create`. Summaries such as `SUM`, `AVERAGE`, and `COUNT` keep totals, averages, and counts up to date. `MIN` and `MAX` work on date fields, so you can show the earliest or latest date. `ARRAYUNIQUE` works on fields that hold more than one value.