Filter lookup column value using JSON

Question

I have a custom list where in the Title column we have 1 to 100 numbers. This Title column we are using in the Lookup column in another list.

Now while using the lookup column list, all the 1 to 100 numbers are getting populated which is as usual. Now we want to control this data in the lookup column - let all numbers (1 to 100) be there in the source list Title column but while using that Title column in the lookup column in another list, we just want to display 50 to 100 numbers.

Using JSON or any other ways will it be doable?

Answer 1

This is not possible using SharePoint JSON formatting.

You have to customize the list forms using Power apps. Follow this:

1. Customize list forms using power apps
2. Go to lookup column combo box (dropdown) control
3. Use Filter function in "items" property of combo box (dropdown) control to filter lookup list items as per your requirements.
4. Publish the forms.

Note: This approach will work only for list forms. This will not work in Grid view (quick edit) of list. So, you might want to disable the grid view (quick edit) from list settings > advanced settings.

For more information, follow article: Filtering Lookup Columns in SharePoint using Power Apps

---

Update:

1. Create a calculated column in lookup source list (say "CalcTitle") like:

   =IF(VALUE([Title])>49,[Title],"")
   

2. Then use "CalcTitle" in lookup column settings instead of "Title" column

Parent list:

Lookup column settings:

Child list form:

Reference: How to filter lookup column based on another column from using specific criteria?