Adding & Managing Conditional Rules
Learn how to create, edit, and manage conditional rules to automate field values in your Knack application.
What You'll Learn
This guide walks you through the process of setting up conditional rules for your fields. You'll discover how to add new rules, edit existing ones, organize multiple rules, and remove rules when they're no longer needed.
Adding Conditional Rules
To add conditional rules to a field:
- Select the DataTable containing the field you want to add a Conditional Rule to
- From the right panel, select the Conditional Rule icon
- Click + Conditional Rule

Conditional Rules
Configure your rule with two main components:
- When: Define one or more conditions that trigger the rule
- Set: Specify what value to assign when conditions are met
Setting Value Options
When configuring what value to set, you have two options:
- To a custom value: Select a specific value to use when the condition is met
- To a field value: Use the value from another field in the same table
For example, you could set a Task Status field to "Pending" if there is no Contact assigned, or set it to "Completed" if there is a Contact assigned.
Comparing to Other Fields
For many operators, you can compare a field to another field rather than to a fixed value:
- When setting up the "When" condition, click the dropdown arrows
- Select another field to compare against
Note: Not all operators support field comparison. For instance, the "is blank" operator only checks if a field has no value and doesn't allow field comparison.
In this example, when the Resolved date is today or before, and the Status is still In Progress or Open, the rule will set the value to Closed, as expected.

Conditional Rule with multiple conditions
Edit, Duplicate, or Delete a Conditional Rule
To modify an existing conditional rule:
- Select the DataTable containing the field with the rule
- Open Conditional Rules in the right panel
- Hover in the conditional rule and select the Edit, Duplicate, or Delete icon.
- Save your changes

Organizing Multiple Rules
When you have multiple conditional rules on a field, they are processed in order from top to bottom. The first rule that matches will be applied, and subsequent rules will be ignored.
Changing Rule Order
To rearrange the order of your rules:
- Click the drag handle icon 🖐️ in the left of the rule
- Drag the rule up or down to the desired position
Place more specific rules at the top and more general rules below them. Always place default rules (rules with no conditions) at the very bottom.
Removing conditional rules will return the field to normal operation, allowing manual updates. Any automated behavior will be lost.
Updated 9 days ago