> For the complete documentation index, see [llms.txt](https://docs.fabricplan.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.fabricplan.com/documentation/plan/powertable-sheets/how-tos/adding-columns-overview/add-visual-column/multi-select-relationship-column.md).
# Multi-select relationship column
A multi-select relationship column lets you associate one or more records from a lookup table with each record in the primary table. It uses a relation table to store the relationships between the primary and lookup tables, enabling many-to-many associations.
By retrieving values from a lookup table, multi-select relationship columns help maintain data consistency, reduce manual data entry, and ensure that users select only valid values.
In this article, you learn how to add a multi-select relationship column to a primary table and add column values that are fetched from the records in a lookup table.
### Prerequisites
Before creating a multi-select relationship column and configuring a many-to-many lookup, make sure that the following tables exist in the database:
* The primary table that contains a primary key and an identifier column.
* The lookup table that contains a primary key, an identifier column, and the selectable values.
* The relation table that contains an identity column and foreign keys that reference the primary key columns in the primary and lookup tables.
{% hint style="info" %}
#### Note
If the required tables do not exist in the database, create or import them to the database before configuring the multi-select relationship column.
You can import them using PowerTable from external sources such as Excel or CSV files. To learn more, see [this section](/documentation/plan/powertable-sheets/how-tos/create-a-table-app-with-powertable-sheets.md).
{% endhint %}
### Add multi-select column
In the following example, you'll add a *Sales Rep* multi-select column to the *Products* table so you can assign one or more sales representatives to each product.
This column retrieves column values from the *Sales Representatives* table (lookup table) using the relationship information obtained from the *Rel\_SalesRep\_Products* table (relation table).
To add a multi-select column:
1. Select **Insert Column** > **Visual Column** > **Add Multi-Select Relationship Column**.
2. Enter a name for the column in the **Column Name**.
3. Enter the lookup table details. This is the table from which the list of values for each record will be retrieved. Use the dropdown menus to select the items listed below.
* Lookup Table: *Sales Representatives*
* Lookup Value: *First Name*
* Lookup Key: *Sales Rep Key*
4. Specify the **relation table**, the **reference column** that stores the lookup table key, and the **identifier columns** used to match records between the primary table and the lookup table. These mappings are used to establish and maintain the relationship between the tables.
Relation table details
This stores or updates the mapping between products and sales reps in the relationship table as we assign and unassign sales reps to the products in the app. Click **Save.**
### Review the multi-select relationship column
We have now successfully added a multi-select relationship column, which allows you to select and assign multiple sales representatives to each product.
Multi-select relationship column
After assigning, you can click **Save** and **Proceed** to save your changes to the database.
Save changes
The relation table is also simultaneously updated based on the selected values.
---
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