## Syntax
```mermaid
%%{init: {
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'themeVariables': {
'fontSize': '11px',
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flowchart LR
Start((START)) --> IS_EMAIL[IS_EMAIL]:::quoted
IS_EMAIL --> End((END))
```
## Purpose
The `IS_EMAIL` SQL function evaluates to `true` when the value provided is a valid email address according to [RFC 822](https://www.w3.org/Protocols/rfc822/).
Parameters:
- Email (`varchar2`): email address.
- Allow plus sign (`boolean`): whether the use of a plus sign ('+') to introduce an alias is allowed. Defaults to `false`.
- Check TLD (`boolean`): indicator whether the TLD of the domain name must be validated against the formal list of defined top-level domains. Defaults to `true`.
Returns: whether the value provided is a valid email address as a `boolean`.
## Examples
The following example verifies conformance of an email address:
```sql
select is_email('
[email protected]')
----------------
true
```
The following example verifies conformance of an email address with an alias:
```sql
select is_email('
[email protected]')
----------------
false
```
The following example verifies conformance of an email address with an alias, which are allowed:
```sql
select is_email('
[email protected]', true)
----------------
true
```
The following example verifies conformance of an email address with an undefined TLD:
```sql
select is_email('
[email protected]')
----------------
false
```