RE: questions about views
- From: "Powell, Mark D" <mark.powell@xxxxxxx>
- To: <oracle-l@xxxxxxxxxxxxx>
- Date: Mon, 16 Jul 2007 09:08:15 -0400
The two queries in a view that produce one column of output might also
be asking how to union two query columns so that only one column
results:
select empno, ename from hourly
union
select empno, Lname || ',' || Fname from salary
order by 2
Hopefully these replies answer what was asked.
-- Mark D Powell --
Phone (313) 592-5148
________________________________
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Niall Litchfield
Sent: Monday, July 16, 2007 7:22 AM
To: skuhn@xxxxxxxxxxxx
Cc: oracle-l@xxxxxxxxxxxxx
Subject: Re: questions about views
Hi Stefan
comments inline
On 7/16/07, Stefan Kuhn <skuhn@xxxxxxxxxxxx> wrote:
Hi all,
I am new to oracle and views and I have two questions:
1. How can I add a new integer columns, which can simply
start with 1 and
count, as a primary key to a view I. e. i have have the
select query, which
is fine, and I just want the new column as the first
column in the table.
It doesn't really make sense to consider a primary key for a
view. A view is, simplifying a bit, a stored query, primary keys apply
to the base tables, not select statements. If you want a pseudo column
that increments by one each time then you can use the construct rownum.
Eg
create or replace view rownum_eg
as
select rownum fake_pk,ename,deptno
from emp
order by deptno,ename;
2. Can I put two queries in one view? I have a table, which has
two columns,
the values of these columns are supposed to go in one
column. No problem to
select one of them, but I have no idea how to do it with
both columns.
Thanks for help
Stefan
In principle anything you can select can be made into a view
(though this is not always wise). I'm reading this question as how to
concatenate two columns. The concatenation operator in Oracle is || so
you might adapt the above example to
create or replace view concat_eg
as
select rownum fake_pk,ename||' Dept: '||to_char(deptno)
Name_and_Number
from emp
order by deptno,ename;
--
Niall Litchfield
Oracle DBA
http://www.orawin.info
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