Re: 2 tables, joins and same name...

On Thu, Aug 30, 2001 at 04:25:41PM -0400, Marc André Paquin wrote:
> Hello,
> 
> Here is 2 tables:
> 
> airport
> ---------
> airport_id
> name
> code
> city_id
> 
> destination
> -----------
> destination_id
> dest_name
> ...
> airport_dep_id  // using airport.airport_id (departure)
> airport_arr_id  // using airport.airport_id  has well (arrival)
> 
> I have 2 columns in the second table that uses the same name column in
> the first table...
> 
> I dont know how to formulate my SQL query... I want to select the
> destinations in the destination table with not the ID of each airport
> but their names. I can do a join with one but with the second one, I get
> no results... And this is confusing!
> 
> select dest.dest_name, air.name as airport1, air.name as airport2 from
> destination, airport air where dest.airport_dep_id_id=air.airport_id and
> dest.airport_arr_id=air.airport_id;

You have to join against the airport table twice:

SELECT dest.dest_name, air1.name as airport1, air2.name as airport2
FROM desination dest, airport air1, airport 2
WHERE dest.airport_dep_id = air1.airport_id AND dest.airport_arr_id = air2.airport_id;

Richard