How to mimic a full outer join using mysql views?
Simulation of FULL OUTER JOIN:

( SELECT ... FROM a LEFT JOIN b ON ... ) -- Intersection, plus rest of b
UNION ALL  -- There will be no overlap; ALL is faster
( SELECT ... FROM b LEFT JOIN a ON ... WHERE a.id IS NULL ) -- Just rest of a


(The link given is less efficient because it gets the Intersection twice, then dedups by doing UNION DISTINCT.)

If you need a FULL OUTER JOIN between more than 2 tables, then it gets messier.  (But you did not ask for that.)