In order to use dependent fields you must have Power Scripts for Jira app installed and enabled.
To use the screen values for a field in the data source, add it as dependent field (from field configuration → Dependencies).
Example: Let's say we have two custom fields: PCF-PRO - Single Autocomplete (let's name it "Continent") and PCF-PRO - Multiple Autocomplete (let's name it "Countries"), the second one is populated depending on the value of the first one.
An easy example is following: we have a table ("countries") with two columns: country and continent. Our first field will select the continents and the second one will contain the countries from that continent.
You can see the corresponding data sources below.
The following data source represents the first custom field:
select distinct continent from countries;
The following data source represents the second custom field:
select country from countries where continent = {customfield_10800}
The following result will be in the issue view screen:
For the moment, dependent fields can only be used by the two custom fields with autocomplete.
From Power Custom Fields PRO 4.0.0, you can now use the dependent fields on SQL data sources as well.
In order to get the value set on the screen for one custom field, you will have to refer it like this: "argv[customfield_id]"