## 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_E164[PHONE_NUMBER_TO_E164]:::quoted
PHONE_NUMBER_TO_E164 --> End((END))
```
## Purpose
The `PHONE_NUMBER_TO_E164` SQL function evaluates to the phone number in [E.164 notation](https://en.wikipedia.org/wiki/E.164) format. In case no country is specified, an E.164 notation is required.
See also [[IS_PHONE_NUMBER]], [[PHONE_NUMBER_TYPE]], [[PHONE_NUMBER_TO_NATIONAL]] 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 E.164 notation format.
## Examples
The following example converts a Dutch national phone number to E.164 notation:
```sql
select phone_number_to_e164('088 002 6500', 'NL')
-------------------
+31880026500
```
The following example converts a Dutch mobile phone number without specifying a country, requiring the phone number to already be in E.164 notation:
```sql
select phone_number_to_e164('+31612345678')
-------------------
+31612345678
```