## Syntax
```mermaid
%%{init: {
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'flowchart': { 'padding': '7', 'nodeSpacing': '20', 'rankSpacing': '20' },
'themeVariables': {
'fontSize': '11px',
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flowchart LR
Start((START)) --> | | IS_EU_VAT_REASON[IS_EU_VAT_REASON]:::quoted
IS_EU_VAT_REASON --> End((END))
```
## Purpose
The `IS_EU_VAT_REASON` SQL function returns the reason the value can not be a valid EU VAT account using a fixed algorithm.
Parameters:
- Value (`varchar2`): value to test.
Returns: reason the value can not be a valid EU VAT account as `varchar2`.
## Examples
The following example returns the reason `'NL123456B01'` is not a valid EU VAT number:
```sql
select is_eu_vat_reason('NL123456B01')
----------------
Invalid VAT number format.: 123456B01.
```