# Variable syntax
<a name="v12-dash-variable-syntax"></a>

****  
This documentation topic is designed for Grafana workspaces that support **Grafana version 12.x**.  
For Grafana workspaces that support Grafana version 10.x, see [Working in Grafana version 10](using-grafana-v10.md).  
For Grafana workspaces that support Grafana version 9.x, see [Working in Grafana version 9](using-grafana-v9.md).  
For Grafana workspaces that support Grafana version 8.x, see [Working in Grafana version 8](using-grafana-v8.md).

Panel titles and metric queries can refer to variables using two different syntaxes.
+ `$varname` – This syntax is easy to read, but it does not allow you to use a variable in the middle of a word.

  **Example:** `apps.frontend.$server.requests.count`
+ `${var_name}` – Use this syntax when you want to use a variable in the middle of an expression.
+ `${var_name:<format>}` – This format gives you more control over how Grafana interprets values. For more information, see *Advanced variable format options*, following this list.
+ `[[varname]]` – Do not use. This syntax is old and has been deprecated. It will be removed in a future release.

Before queries are sent to your data source the query is *interpolated*, meaning the variable is replaced with its current value. During interpolation, the variable value might be *escaped* in order to conform to the syntax of the query language and where it is used. For example, a variable used in a regex expression in an InfluxDB or Prometheus query will be regex escaped.

**Advanced variable format options**

The formatting of the variable interpolation depends on the data source, but there are some situations where you might want to change the default formatting.

For example, the default for the MySQL data source is to join multiple values as comma-separated with quotes: `'server01','server02'`. In some cases, you might want to have a comma-separated string without quotes: `server01,server02`. You can make that happen with advanced variable formatting options listed below.

**General syntax**

Syntax: `${var_name:option}`

If any invalid formatting option is specified, then `glob` is the default/fallback option.

**CSV**

Formats variables with multiple values as a comma-separated string.

```
servers = [ 'test1',  'test2' ]
String to interpolate:  '${servers:csv}'
Interpolation result:  'test1,test2'
```

**Distributed - OpenTSDB**

Formats variables with multiple values in custom format for OpenTSDB.

```
servers = [ 'test1',  'test2' ]
String to interpolate:  '${servers:distributed}'
Interpolation result:  'test1,servers=test2'
```

**Doublequote**

Formats single- and multi-valued variables into a comma-separated string, escapes `"` in each value by `\"` and quotes each value with `"`.

```
servers = [ 'test1',  'test2' ]
String to interpolate:  '${servers:doublequote}'
Interpolation result:  '"test1","test2"'
```

**Glob - Graphite**

Formats variables with multiple values into a glob (for Graphite queries).

```
servers = [ 'test1',  'test2' ]
String to interpolate:  '${servers:glob}'
Interpolation result:  '{test1,test2}'
```

**JSON**

Formats variables with multiple values as a comma-separated string.

```
servers = [ 'test1',  'test2' ]
String to interpolate:  '${servers:json}'
Interpolation result:  '["test1", "test2"]'
```

**Lucene - Elasticsearch**

Formats variables with multiple values in Lucene format for Elasticsearch.

```
servers = [ 'test1',  'test2' ]
String to interpolate:  '${servers:lucene}'
Interpolation result:  '("test1" OR "test2")'
```

**Percentencode**

Formats single and multivalued variables for use in URL parameters.

```
servers = [ 'foo()bar BAZ',  'test2' ]
String to interpolate:  '${servers:percentencode}'
Interpolation result:  'foo%28%29bar%20BAZ%2Ctest2'
```

**Pipe**

Formats variables with multiple values into a pipe-separated string.

```
servers = [ 'test1.',  'test2' ]
String to interpolate:  '${servers:pipe}'
Interpolation result:  'test1.|test2'
```

**Raw**

Turns off data source-specific formatting, such as single quotes in an SQL query.

```
servers = [ 'test.1',  'test2' ]
String to interpolate:  '${var_name:raw}'
Interpolation result:  'test.1,test2'
```

**Regex**

Formats variables with multiple values into a regex string.

```
servers = [ 'test1.',  'test2' ]
String to interpolate:  '${servers:regex}'
Interpolation result:  '(test1\.|test2)'
```

**Singlequote**

Formats single- and multi-valued variables into a comma-separated string, escapes `'` in each value by `\'` and quotes each value with `'`.

```
servers = [ 'test1',  'test2' ]
String to interpolate:  '${servers:singlequote}'
Interpolation result:  "'test1','test2'"
```

**Sqlstring**

Formats single- and multi-valued variables into a comma-separated string, escapes `'` in each value by `''` and quotes each value with `'`.

```
servers = [ "test'1",  "test2" ]
String to interpolate:  '${servers:sqlstring}'
Interpolation result:  "'test''1','test2'"
```

**Text**

Formats single- and multi-valued variables into their text representation. For a single variable, it will just return the text representation. For multi-valued variables, it will return the text representation combined with `+`.

```
servers = [ "test1",  "test2" ]
String to interpolate:  '${servers:text}'
Interpolation result:  "test1 + test2"
```

**Query parameters**

Formats single- and multi-valued variables into their query parameter representation. Example: `var-foo=value1&var-foo=value2`

```
servers = [ "test1",  "test2" ]
String to interpolate:  '${servers:queryparam}'
Interpolation result:  "var-servers=test1&var-servers=test2"
```