MySQL Error: 1054 Unkown column in 'where clause'

Question

I am creating a view with the query shown below:

create view v2 as
(select * from appearance a
where exists (
    select p.id from photo p, photographer u, person s
    where p.takenBy = u.id
    and u.id = s.id
    and a.isShownIn = p.id
    and s.name = 'Fred'
    )
);

The appearance table has 2 columns 'shows' and 'isShownIn' but when i try to insert in the view, it gives me error as Error Code: 1054. Unknown column 'a.isShownIn' in 'where clause'

While browsing over this I cam over that I am mistaking over alias, but everything looks OK to me, could anyone please point out where could be the error?

Thanks!

Answer 1

You will not be able to insert in a view created in that way. Only certain views are updateable. In your specific case, you should just insert into appearance table, since your view is just a selection from that table.

For limitations for updateable views, check this out. Your view has this problem: "A subquery in the WHERE clause that refers to a table in the FROM clause"

Like @Umbrella suggested, you can use join instead of exists, and in that way, you would avoid inner query, and you might have updateable view, but I really think that there is no need to insert into that view, because you will have the same effect by just inserting into appearance table.

Answer 2

Why are you using exists()? Why not just join them...

create view v2 as
select a.* 
from appearance a, photo p, photographer u, person s
where a.isShownIn = p.id
  and p.takenBy = u.id
  and u.id = s.id
  and s.name = 'Fred'