## Syntax
```mermaid
%%{init: {
'theme': 'base',
'flowchart': { 'padding': '7', 'nodeSpacing': '20', 'rankSpacing': '20' },
'themeVariables': {
'fontSize': '11px',
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}}%%
flowchart LR
Start((START)) --> | | PHONE_NUMBER_TO_NATIONAL[PHONE_NUMBER_TO_NATIONAL]:::quoted
PHONE_NUMBER_TO_NATIONAL --> End((END))
```
## Purpose
The `PHONE_NUMBER_TO_NATIONAL` SQL function evaluates to the phone number in national notation format. In case no country is specified, an E.164 notation is required.
See also [[IS_PHONE_NUMBER]], [[PHONE_NUMBER_TYPE]], [[PHONE_NUMBER_TO_E164]] and [[PHONE_NUMBER_TO_INTERNATIONAL]].
Parameters:
- Phone (`varchar2`): phone number as text.
- Country (optional, `varchar2`): country code as ISO 3166-1 alpha-2 code.
Returns: Phone number in national notation format.
## Examples
The following example converts a phone number in E.164 notation to Dutch national notation:
```sql
select phone_number_to_national('+31880026500')
-------------------
088 002 6500
```
The following example interprets the same digits as a Swiss phone number, resulting in a different national notation:
```sql
select phone_number_to_national('0880026500', 'CH')
-------------------
880026500
```