Title: WP_Tax_Query::sanitize_relation
Published: December 18, 2014
Last modified: May 20, 2026

---

# WP_Tax_Query::sanitize_relation( string $relation ): string

## In this article

 * [Parameters](https://developer.wordpress.org/reference/classes/wp_tax_query/sanitize_relation/?output_format=md#parameters)
 * [Return](https://developer.wordpress.org/reference/classes/wp_tax_query/sanitize_relation/?output_format=md#return)
 * [Source](https://developer.wordpress.org/reference/classes/wp_tax_query/sanitize_relation/?output_format=md#source)
 * [Related](https://developer.wordpress.org/reference/classes/wp_tax_query/sanitize_relation/?output_format=md#related)
 * [Changelog](https://developer.wordpress.org/reference/classes/wp_tax_query/sanitize_relation/?output_format=md#changelog)

[ Back to top](https://developer.wordpress.org/reference/classes/wp_tax_query/sanitize_relation/?output_format=md#wp--skip-link--target)

Sanitizes a ‘relation’ operator.

## 󠀁[Parameters](https://developer.wordpress.org/reference/classes/wp_tax_query/sanitize_relation/?output_format=md#parameters)󠁿

 `$relation`stringrequired

Raw relation key from the query argument.

## 󠀁[Return](https://developer.wordpress.org/reference/classes/wp_tax_query/sanitize_relation/?output_format=md#return)󠁿

 string Sanitized relation. Either `'AND'` or `'OR'`.

## 󠀁[Source](https://developer.wordpress.org/reference/classes/wp_tax_query/sanitize_relation/?output_format=md#source)󠁿

    ```php
    public function sanitize_relation( $relation ) {
    	if ( 'OR' === strtoupper( $relation ) ) {
    		return 'OR';
    	} else {
    		return 'AND';
    	}
    }
    ```

[View all references](https://developer.wordpress.org/reference/files/wp-includes/class-wp-tax-query.php/)
[View on Trac](https://core.trac.wordpress.org/browser/tags/7.0/src/wp-includes/class-wp-tax-query.php#L207)
[View on GitHub](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/class-wp-tax-query.php#L207-L213)

## 󠀁[Related](https://developer.wordpress.org/reference/classes/wp_tax_query/sanitize_relation/?output_format=md#related)󠁿

| Used by | Description | 
| [WP_Tax_Query::sanitize_query()](https://developer.wordpress.org/reference/classes/wp_tax_query/sanitize_query/)`wp-includes/class-wp-tax-query.php` |

Ensures the ‘tax_query’ argument passed to the class constructor is well-formed.

  | 
| [WP_Tax_Query::__construct()](https://developer.wordpress.org/reference/classes/wp_tax_query/__construct/)`wp-includes/class-wp-tax-query.php` |

Constructor.

  |

## 󠀁[Changelog](https://developer.wordpress.org/reference/classes/wp_tax_query/sanitize_relation/?output_format=md#changelog)󠁿

| Version | Description | 
| [4.1.0](https://developer.wordpress.org/reference/since/4.1.0/) | Introduced. |

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