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filter is not described

terms_clauses filter-hook . WP 3.1.0

Filters the terms query SQL clauses.

Usage

add_filter( 'terms_clauses', 'filter_function_name_9794', 10, 3 );
function filter_function_name_9794( $pieces, $taxonomies, $args ){
	// filter...

	return $pieces;
}
$pieces(array)
Terms query SQL clauses.
$taxonomies(array)
An array of taxonomies.
$args(array)
An array of terms query arguments.

Where the hook is called

WP_Term_Query::get_terms()
wp-includes/class-wp-term-query.php 647
$clauses = apply_filters( 'terms_clauses', compact( 'fields', 'join', 'where', 'distinct', 'orderby', 'order', 'limits' ), $taxonomies, $args );

Where the hook is used (in WP core)

Does not used.