Re: [HACKERS] Views on aggregates - need assistence - Mailing list pgsql-hackers

On Mon, 23 Feb 1998, Bruce Momjian wrote:

> >
> > On Mon, 23 Feb 1998, Bruce Momjian wrote:
> >
> > > Actually, it does handle unions of views, but not views of unions.
> > > Informix doesn't support it either, and I don't know what the other
> > > dbms's do, but I think I am going to find out soon from someone.  :-)
> >
> >     What exactly would you like me to try here? *raised eyebrow*
> >
> >
> >
>
>
>     create view as
>         select oid from pg_user union select oid from pg_class
>
> or something like that.  That will not work under PostgreSQL.  But you
> can use views as part of a union:
>
>     select oid from view1
>     union
>     select oid from view2

You mean like:

SQL> select * from one
  2  ;

         A
----------
         3
         4
         2

SQL> create table two ( B int );

Table created.

SQL> insert into two values ( 1 );

1 row created.

SQL> insert into two values ( 2 ) ;

1 row created.

SQL> insert into two values ( 3 ) ;

1 row created.

SQL> create view v1 as select A from one union select B from two;

View created.

SQL> select * from v1;

         A
----------
         1
         2
         3
         4