Here is the sample query for Grafana Dashboard variables based on the datas source used.

1. MySQL
=====
Nested Filter POC Dashboard
---------------------------
Variable Definition
$hostname SELECT hostname FROM grafana_teting
$subhost SELECT subhost FROM grafana_teting WHERE hostname =
$hostname
-------------------------------------------------------------------------
-------------------------------------------------------------
Elasticsearch
=============
Variable Definition
$Filters
$NewFilter 1,2,3,5,10
Variable Definition
$source {"find": "terms", "field": "@source"}
$host {"find": "terms", "field": "@hostname", "query":
"@source:$source"}
$adhoc
-------------------------------------------------------------------------
-------------------------------------------------------------
Graphite
========
Variable Definition
$app apps.*
$server apps.$app.*
$interval 1m,10m,30m,1h,6h,12h,1d,7d,14d,30d
Variable Definition
$servers_users servers
$serversN_usersN _test-data.$servers_users.*
$requests_data _test-data.$servers_users.$serversN_usersN.*
$count _test-
data.$servers_users.$serversN_usersN.$requests_data.*
-------------------------------------------------------------------------
-------------------------------------------------------------
InfluxDB
========
Variable Definition
$datacenterSHOW TAG VALUES WITH KEY = "datacenter"
$host SHOW TAG VALUES WITH KEY = "hostname" WHERE "datacenter" =~
/^$datacenter$/
$summarize 1m,10m,30m,1h,6h,12h,1d,7d,14d,30d
$adhoc
-------------------------------------------------------------------------
-------------------------------------------------------------
Prometheus
==========
Variable Definition
$node label_values(node_load1{job="node"}, instance)
$filesystem_mountpoint query_result(node_filesystem_size{job="node",
instance=~"$node:.*", device=~"/dev/.*",
mountpoint!="/var/lib/docker/aufs"})