Question

I have two tables with multiple connections, for example:

First table: Tbl_Flights, it has fields City_From and City_To, containing city’s key.
Also, there is a table called Tbl_Cities, which has unique counter field and field for city name.

How to create a query which will possible to print out all the flights from table Tbl_Flights with departure and arrival city names, like:

From               To
------------------------------
Moscow             New York
Amsterdam          Paris
Helsinki           Tallin

Does double INNER JOIN solve the problem?

Answer 1

Does double INNER JOIN solve the problem?

Yes, it does. But they are two INNER JOINs to the same table Cities, so that you can select the CiteName column into two different columns From, to.

Like so:

SELECT 
  f.FlightName,
  FromCities.cityName "From",
  ToCities.CityName "To"
FROM Tbl_Flights f
INNER JOIN Cities FromCities ON f.City_From = FromCities.CityID
INNER JOIN Cities ToCities   ON f.City_To   = ToCities.CityID;

SQL Fiddle Demo

This will give you:

| FLIGHTNAME |      FROM |       TO |
-------------------------------------
|    Flight1 |    Moscow | New York |
|    Flight2 | Amsterdam |    Paris |
|    Flight3 |  Helsinki |   Tallin |