Hi @murarisaranvikas, welcome to the community!
This post in the community has a lot of great information about how to use the value mapping feature with regex to edit values that show up in your graph.
I think we could definitely use more examples, so I mocked up your query with CSV data and
a bar chart to show an example of how you could remove the end of the value name in your bar chart.
To transform this:
Into this, removing the _exporter string at the end:
You can use a value mapping in the bar gauge options in the sidebar of the panel editor.
When you click Add value mappings it opens with a default Value mapping not Regex.
Click the Add a value mapping button, and choose Regex from the dropdown to add the regex value mappng and substitution. You can delete the default value mapping.
The regex (.*)_.* will capture everything up to the last underscore and $1 will substitute that as the new value.
The site https://regex101.com/ is a really helpful tool to test out regex. You’ll want to change the flavor to golang to get the right interpretations for Grafana.