How to add custom metrics to mysqld_exporter integration?


I am quite new to grafana cloud agent. Need some help on mysql exporter integration.

If I want to add some custom metrics, for example,

select count(*) from information_schema.processlist;

What is the right way to add it into existing mysqld_exporter integration section?
Can I add multiple queries?

  enabled: true
  data_source_name: root@(server-a:3306)/
  - source_labels: [__address__]
    target_label: instance
    replacement: server-a

Thank you