Documentation Plugins Oracle data source Template variables

Oracle template variables

Use template variables to create dynamic, reusable dashboards. Instead of hard-coding details such as server names, applications, or regions in your queries, you can use variables that appear as drop-down selectors at the top of the dashboard.

Before you begin

• Configure the Oracle data source.
• Understand Grafana template variables.

Supported variable types

Create a query variable

To create a query variable:

1. Navigate to Dashboard settings > Variables.
2. Click Add variable.
3. Select Query as the variable type.
4. Select the Oracle data source.
5. Enter a SQL query that returns the values you want as variable options.

For detailed instructions, refer to Add a query variable.

Query examples

An Oracle variable query returns column values that populate the variable drop-down.

Single column

Return all values from a single column:

SQL Copy

SELECT hostname FROM host

Multiple columns

A query can return multiple columns. Grafana creates a combined list from all returned columns:

SQL Copy

SELECT host.hostname, other_host.hostname2
FROM host
JOIN other_host ON host.city = other_host.city

Key/value variables

Return two columns named __text and __value to create a variable where the display name differs from the stored value. The __text column values must be unique:

SQL Copy

SELECT hostname AS __text, id AS __value
FROM host

Time-dependent variables

To use time range macros like $__timeFilter(column) in your variable query, set the variable refresh to On Time Range Change:

SQL Copy

SELECT event_name
FROM event_log
WHERE $__timeFilter(time_column)

Chained variables

Create nested variables by referencing one variable inside another. For example, create a region variable, then use it to filter a hosts variable:

SQL Copy

SELECT hostname
FROM host
WHERE region = '$region'

Use variables in queries

Reference variables in your Oracle queries using the $variable or ${variable} syntax.

Multi-value variables

If a variable allows multiple selections, use the IN operator instead of =:

SQL Copy

SELECT *
FROM host
WHERE hostname IN ($hostname)

Grafana interpolates multi-value variables as single-quoted, comma-separated values (for example, 'host1','host2','host3').

Variable syntax reference

For the full variable syntax including advanced formatting options, refer to Variable syntax.