Re: SELECT col_a, (SELECT col_b .....

Hi Frank,

The name I know it by is an "inline view".. You're right...it could be written in the "old" style as you've shown it if table b exists..
The benefit of the inline view is that your SELECT in your from clause can produce a set of records that don't exist as a permanent table..e.g. joins, group functions, etc.

Hope this helps clarify it,

Steve

Frank wrote:

> Hi!
> Oracle 8.1.6/Windows2000
>
> I have found that Oracle now handles queries with the form:
> SELECT col_a,
> (SELECT col_b FROM table_b WHERE find only one row)
> FROM table_a a
> WHERE find stuff;
>
> What is this construction called ? (so I can search for it in the
> documentation)
> How does Orcale optimize this ?
> It seems to me that a expression like this could be rewritten to a "old"
> query like:
> SELECT col_a, col_b
> FROM table_a a, table_b
> WHERE a.id=b.id(+);
>
> Is that happening behind the scenery?
>
> Frank
  Received on Sat Jul 21 2001 - 16:26:58 CDT