Related parameters are not working

Hello!
I want to create parameters that depend on each other.
Here are the queries:

select distinct app from apps;
select distinct source from sources where app_name IN ({{AppName}}));
select distinct campaign from campaigns where app_name IN ({{AppName}})) and media_source IN ({{MediaSource}}));

But the third request fails because the source parameter is not loading.
Can you tell me a way to solve this problem?
Thanks a lot!

The third query fails because the second query uses parameters. When you use “Query Based Dropdown List” parameters, the target query cannot itself use parameters.

Thank you for reply!
It’s very inconvenient. Is it possible to add such functionality?
In my case, every source contains a big number of campaigns. And if user chooses one of the sources, it is preferable to show campaigns only from this source
Thanks!

It’s a good idea. Just not on the roadmap for now. Big discussion here: