I'm reading "SQL for dummies" and one of the more interesting sections
was on recursion. The example query was something like:
WITH RECURSIVE
ReachableFrom (Source, Destination)
AS (SELECT Source, Destination
FROM FLIGHT
UNION
SELECT in.Source, out.Destination
FROM ReachableFrom in, FLIGHT out
WHERE in.Destination = out.Source
)
SELECT * FROM ReachableFrom
WHERE Source = "Portland";
I'm a bit thrown by the union. Can this be simplified to:
WITH RECURSIVE
ReachableFrom (Source, Destination)
AS (SELECT Source, Destination
FROM FLIGHT
)
SELECT * FROM ReachableFrom
WHERE Source = "Portland";
thanks,
Thufir
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