public function joins(array $joins, $context) {
		$result = null;

		foreach ($joins as $key => $join) {
			if ($result) {
				$result .= ' ';
			}
			$join = is_array($join) ? $this->_instance('query', $join) : $join;
			$options['keys'] = ['mode', 'source', 'alias', 'constraints'];
			$result .= $this->renderCommand('join', $join->export($this, $options));
		}
		return $result;
	}