wpdb::set_blog_id( int $blog_id, int $network_id )

	public function set_blog_id( $blog_id, $network_id = 0 ) {
		if ( ! empty( $network_id ) ) {
			$this->siteid = $network_id;
		}

		$old_blog_id  = $this->blogid;
		$this->blogid = $blog_id;

		$this->prefix = $this->get_blog_prefix();

		foreach ( $this->tables( 'blog' ) as $table => $prefixed_table )
			$this->$table = $prefixed_table;

		foreach ( $this->tables( 'old' ) as $table => $prefixed_table )
			$this->$table = $prefixed_table;

		return $old_blog_id;
	}