Re: How to do? - Mailing list pgsql-general

On Fri, 2003-08-01 at 11:44, Robert Partyka wrote:
> Ron Johnson wrote:
>  > No, but slightly ambiguous, at least for my old brain.
> I will try to by more unequivocal this time :)
>
> Shridhar Daithankar wrote:
>  > select oid,name from a;
> I know it, but i have to have not oid's but row numbers :) such like :
>      table "test"
>     offset  |   value
> -----------+------------
> 1          |    AC43
> 2          |    AC4X
> 3          |    AX43
> 4          |    ACX3
> ....
> n          |    XC4A
>
> the best will be without using sequence :)

But relational algebra and SQL don't have the concept of row numbers.
"row numbers" like OIDs are internal constructs that are exposed to
the users, but shouldn't be used.

> Shridhar Daithankar wrote:
>  > I didn't get that.. could you please elaborate?
>
> Franco Bruno Borghesi wrote:
>  > And about the rows before and after that you ask, I don't understand...
> based on what you mean
>  > *before* and *after*? you don't have an order by clause.
>
>  > And what do you mean with "I know that in result is record with e.g.
> uid='AC13A1'"?
>  > You know this uid *before* sending the query? is it part of your <where
> statement>? can you use
>  > this value as a hard coded condition for a subquery?
>
> Ok, so its goes something like that:
>
> lets say i have select query: select a,b,uid from foo where c='bar' order by a;
>
> with results like that:
>   a  | b  | uid
> ----+----+------
> 2   |x   | AC01
> 2   |w   | AC43
> 4   |d   | AC88
> 4   |a   | AC13
> ...
> 7   |c   | AC22
>
>
> and lets say I selected this before and I know that there is uid='AC88';
>
> and in another connection (in lets say next requested www php script )
> without selecting all
> this data or even full list of only uid`s and making sequence scan row by
> row I wont to get
> something like that from select I have write above:
>
>   a  | b  | uid
> ----+----+------
> 2   |w   | AC43
> 4   |d   | AC88
> 4   |a   | AC13
> (3 rows)
>
> if there is row before and row next of uid='AC88' or
>
>   a  | b  | uid
> ----+----+------
> 2   |w   | AC43
> 4   |d   | AC88
> (2 rows)
> if uid='AC88' is last one row
>
> or
>
>   a  | b  | uid
> ----+----+------
> 4   |d   | AC88
> 4   |a   | AC13
> (2 rows)
> if uid='AC88' is first row
>
> I hope its more understandable than before :)
>
> regards
> Robert 'BoBsoN' Partyka
>
>
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