Nested Ansichten Problem in mysql

Question

CREATE or REPLACE VIEW myView AS 
SELECT t2.film_id, t2.no_actors AS n_actor, COALESCE(t1.no_copies,0) AS n_inventory FROM 
(SELECT film_id, count(film_id) AS no_copies FROM inventory GROUP BY film_id) AS t1 RIGHT OUTER JOIN 
(SELECT film_id, count(actor_id) 
AS no_actors FROM film_actor GROUP BY film_id) AS t2 
ON t2.film_id=t1.film_id; 

Die obige Abfrage gibt den Fehler:

ERROR 1349 (HY000): View's SELECT contains a subquery in the FROM clause 

Wie wir verschachtelte Ansichten für die obige Abfrage in einer einzigen Abfrage schreiben? Bitte helfen. Danke im Voraus.

Answer 1

Sie können keine Unterabfrage in create view verwenden, aber Sie können andere Ansichten auf diese Weise

CREATE or REPLACE VIEW myViewSub1 AS 
SELECT film_id, count(film_id) AS no_copies FROM inventory GROUP BY film_id 
; 


CREATE or REPLACE VIEW myViewSub2 AS 
SELECT film_id, count(actor_id) 
AS no_actors FROM film_actor GROUP BY film_id 
; 

CREATE or REPLACE VIEW myView AS 
SELECT t2.film_id, t2.no_actors AS n_actor, COALESCE(t1.no_copies,0) AS n_inventory 
FROM myViewSub1 AS t1 
RIGHT OUTER JOIN myViewSub2 AS t2 
ON t2.film_id=t1.film_id 
;