Question

I am trying to do a multiple join like this

SELECT * FROM (((Customer FULL JOIN Booking ON Customer.ID = Booking.CustID) 
FULL JOIN Flight ON Booking.FlightID = Flight.ID) 
FULL JOIN FlightRoute ON Flight.RouteID = FlightRoute.ID)

But it is syntactically incorrect according to mysql. Please help

Answer 1

There is no FULL JOIN in MySQL. It’s convoluted but a FULL JOIN is equivalent to a UNION ALL between a LEFT JOIN and a RIGHT JOIN, using a condition to remove duplicates. It’s late in the day and the thought of your 3 FULL JOINs in that statement is hurting my head.

You do say in Conrad Frix’s answer that removing the FULL makes it work, if it does then you have misunderstood how FULL JOINs and INNER JOINs work.

For the first FULL JOIN it would look like:

SELECT * FROM Customers c
   LEFT JOIN Booking b ON c.ID = b.CustId
UNION ALL
SELECT * FROM Customers c
   RIGHT JOIN Booking b ON c.ID = b.CustId
WHERE c.ID IS NULL

Use that basis to form the rest of your statements.