## Syntax
```mermaid
%%{init: {
'theme': 'base',
'flowchart': { 'padding': '7', 'nodeSpacing': '20', 'rankSpacing': '20' },
'themeVariables': {
'fontSize': '11px',
'fontFamily': 'Arial'
}
}}%%
flowchart LR
Start((START)) --> NULL[NULL]:::quoted
NULL --> End((END))
```
## Purpose
The "unknown" value `null`.
See also [[NVL]] and [[COALESCE]].
## Examples
The following example retrieves the "unknown" value `null`; the output is empty:
```sql
select null
-------------------
```