sql server join 3 tables, not in other column of third table - sql-server

Question

So, i have two tables which are connected by a third one.
Something like:
First Table:
+------------+--------------+--------------+------------+
| box_column | code_column | from_column | to_column |
+------------+--------------+--------------+------------+
| 12345 | sdsad1 | madrid | london |
+------------+--------------+--------------+------------+
Second Table:
+-------------+--------------+
| code_column | truck_column |
+-------------+--------------+
| sdsad1 | truck1 |
| sdsad1 | truck2 |
| sdsad1 | truck3 |
+-------------+--------------+
Third Table:
+--------------+-------------+-----------+
| truck_column | from_column | to_column |
+--------------+-------------+-----------+
| truck1 | madrid | paris |
| truck2 | paris | calais |
| truck3 | calais | london |
+--------------+-------------+-----------+
after having a join, just having the number of the box, is there any way i can distinct the trucks that make the last leg (third table have london in the to_column) and the others?

Answer 1

That is not very difficult to do, it's actually quite basic:
SELECT *
FROM dbo.code c
INNER JOIN dbo.jointable j on c.code = j.code
INNER JOIN dbo.truck t on j.truck = t.truck
WHERE c.box = 12345
AND c.[to] = t.[to]
Where code is your first table, jointable is your second table, and truck is your third table.
The output of this query is:
box code from to code truck truck from to
---------------------------------------------------------------------
12345 sdsad1 madrid london sdsad1 truck3 truck3 calais london
To get only the truck as output, replace
SELECT *
with
SELECT t.truck
Last but not least: I'm not seeing any primary keys, nor foreign keys in your model. Maybe you left it out. If not, please use keys and constraints.