How to set up the Query in Templating?

Grafana Prometheus
1

I have set up the host and program.
In Query Options,the query is label_values(host) and other is label_values(program).
But they are not related. I mean I first select the host, then select the program which in this host.
I try to use label_values(host,program), but it does not work.
Can you help me?

2

Did you get this working?

Can you give more details on this. How does it not work?

3

Thank you for your reply.
When I use label_values{host}, I can get 192.168.108.xxx. About twenty options.
When I use label_values{post}, I can get every process I name, like bs_0001, bs_0002, …
When I use label_values(host,program), the Preview of values is none, and the metric is {host="$host", program="$program"} in graph is no data.

I want to select program only in selected host.
Thanks again.