6.5.1 Using Null Display Value
When using the Select List, Radio Group, and Popup LOV
you can optionally include an item in the list that represents the null
value, and if included it can have a custom label.
This can be useful to help an end user understand what not selecting a value means. For example, consider the Department Select List page item below used as an optional query by example criteria field. The Null Display Value of "<All>" suggests that employees from all departments will be shown if they don't select a specific department.
Figure 6-25 Custom Label Representing the Null Value in a Select List
Parent topic: Using Page Items for Query by Example