What Grafana version and what operating system are you using?
Grafana version: v7.5.3
Data source type & version: Iotdb-Grafana and simpejson
OS Grafana is installed on: Windows 10
User OS & Browser: Chrome on Windows 10
Grafana plugins: Only built-in plugins
What are you trying to achieve?
use the variables to control the Hide A Query button,
When select different variables, the line chart will draw different chart.