# Creating lookups and rollups between tables

Stacker allows you to create lookup and roll-up fields directly within your app. This means you can pull together and summarise data from different data sources.

Lookups and Rollups each work over records which are linked by a relationship ("link to another record") field. So it only offers you tables where there is a valid relationship.

1. Click **Manage fields and data**
2. Click **Fields** > **+ Add field**
3. Enter a field name
4. Select the Lookup or Roll-up field type
5. Select the linked record field to use in the Lookup or Roll-up.
6. Select the field from the linked record that you want to look up or roll-up.
7. Click **Save**

![lookup\_fields.gif](https://support.stackerhq.com/hc/article_attachments/15481968706707)

You should now have the new field on your Data Grid.

**Tip**

We suggest choosing a name that clearly reflects the data that will be pulled in or summarised, e.g. 'Client Notes Lookup'.

### Lookup Field

A lookup field shows a specific field from a linked table. On our Properties app we have created a lookup field from our Clients table to our Team table. Instead of showing the Primary field, this allows you to choose any field to display.

![Screenshot\_2022-07-25\_at\_16.30.02.png](https://support.stackerhq.com/hc/article_attachments/8078967063443/Screenshot_2022-07-25_at_16.30.02.png)

### Roll-up Field

A roll-up field can display different results of a field based on related records.

Possible display options:

* Number of related records
* Count values...
* Sum...
* Average...
* Min...
* Max...

![CleanShot\_2023-04-04\_at\_13.02.53\_2x.png](https://support.stackerhq.com/hc/article_attachments/15481609845523)