Can you change this to:
```php
$this->db->query('
	SELECT *
	FROM planet_is_building
	JOIN planet_can_build USING(planet_type_id, construction_id)
	WHERE game_id = ' . $this->db->escapeNumber($this->getGameID()) . '
	AND sector_id = ' . $this->db->escapeNumber($this->getSectorID()) . '
	AND planet_type_id = ' . $this->getTypeID()
);
```

I've also added planet_type_id to the join, I figure it should be there?