WP_Site_Query::get_search_sql() WordPress Method

	protected function get_search_sql( $search, $columns ) {
		global $wpdb;

		if ( false !== strpos( $search, '*' ) ) {
			$like = '%' . implode( '%', array_map( array( $wpdb, 'esc_like' ), explode( '*', $search ) ) ) . '%';
		} else {
			$like = '%' . $wpdb->esc_like( $search ) . '%';
		}

		$searches = array();
		foreach ( $columns as $column ) {
			$searches[] = $wpdb->prepare( "$column LIKE %s", $like );
		}

		return '(' . implode( ' OR ', $searches ) . ')';
	}