Select and join on dynamic table name - mysql

Question

I would like to get all information about every item. Items has global variable (here on_stock), but every item has also its own property in different table, and that table has the same name as the items type name.
select items
join its type_id on types table id -> name
join selected item on name.id
Here is the sample:
[items]
id | on_stock | type_id
-----+----------+-----------
1 1 1(=car)
2 0 1(=car)
3 1 2(=ship)
4 0 2(=ship)
[types]
id | name
----+--------
1 car
2 ship
[car]
id | top_speed
----+-----------
1 200
2 300
[ship]
id | color
-----+-------
3 red
4 blue
expected result:
1 on_stock=1 top_speed=200
2 on_stock=0 top_speed=300
3 on_stock=1 color=red
4 on_stock=0 color=blue
Please help to achieve this!

Answer 1

If I could not do it in one request, I'll do it in more(1+item types count).
first, I need the required types as array(id=>name):
$req_types = array();
$rs = mysql_query("
SELECT items.type_id,types.name
FROM items
JOIN types ON items.type_id=type.id
GROUP BY items.type_id
");
while($type= mysql_fetch_assoc($rs))
$req_types[$type['id']] = $type['name'];
then I need the common and individual item data:
$groups = array();
foreach($req_types as $table)
{
$rs = mysql_query("
SELECT items.*,$table.*
FROM items
JOIN $table ON $table.id=items.id
");
while($item = mysql_fetch_assoc($rs))
$groups[$table][] = $item;
}

Answer 2

It isn't pretty, but neither is the data structure. Here is a query to do what you want
SELECT I.id, I.On_stock, C.top_speed,S.Color
FROM ITEMS I
LEFT JOIN Car C ON (I.ID = C.CarID)
LEFT JOIN Ship S ON (I.ID = S.ShipID)
You will have to tweak the query every time you add a new item type, but that is just a downside of this data structure.