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* Support for SQL TOP clause?
@ 2008-01-10 03:13 Chinyi Woo <chinyi.woo@gmail.com>
0 siblings, 2 replies; 4+ messages in thread
From: Chinyi Woo @ 2008-01-10 03:13 UTC (permalink / raw)
To: pgsql-sql
Hello, everyone
Does Postgresql support query like SELECT *TOP 3* * FROM Individual ? If I
use ORDER BY, I have to write non-sql code to get the first row in the
result set, which I try to avoid.
Thanks
Chinyi
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: Support for SQL TOP clause?
@ 2008-01-10 03:19 Phillip Smith <phillip.smith@weatherbeeta.com.au>
parent: Chinyi Woo <chinyi.woo@gmail.com>
1 sibling, 1 reply; 4+ messages in thread
From: Phillip Smith @ 2008-01-10 03:19 UTC (permalink / raw)
To: 'Chinyi Woo' <chinyi.woo@gmail.com>; pgsql-sql
SELECT *
FROM Individual
LIMIT 3
I asked the reverse question moving from PG to MSSQL :-(
-----Original Message-----
From: pgsql-sql-owner@postgresql.org [mailto:pgsql-sql-owner@postgresql.org]
On Behalf Of Chinyi Woo
Sent: Thursday, 10 January 2008 14:14
To: pgsql-sql@postgresql.org
Subject: [SQL] Support for SQL TOP clause?
Hello, everyone
Does Postgresql support query like SELECT TOP 3 * FROM Individual ? If I
use ORDER BY, I have to write non-sql code to get the first row in the
result set, which I try to avoid.
Thanks
Chinyi
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^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: Support for SQL TOP clause?
@ 2008-01-10 11:46 Reinoud van Leeuwen <reinoud.v@n.leeuwen.net>
parent: Phillip Smith <phillip.smith@weatherbeeta.com.au>
0 siblings, 0 replies; 4+ messages in thread
From: Reinoud van Leeuwen @ 2008-01-10 11:46 UTC (permalink / raw)
To: pgsql-sql
On Thu, Jan 10, 2008 at 02:19:43PM +1100, Phillip Smith wrote:
> SELECT *
>
> FROM Individual
>
> LIMIT 3
Note that you will have to add an 'order by' clause to guarantee
predictable results...
--
__________________________________________________
"Nothing is as subjective as reality"
Reinoud van Leeuwen reinoud.v@n.leeuwen.net
http://www.xs4all.nl/~reinoud
__________________________________________________
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: Support for SQL TOP clause?
@ 2008-01-10 13:56 Richard Broersma Jr <rabroersma@yahoo.com>
parent: Chinyi Woo <chinyi.woo@gmail.com>
1 sibling, 0 replies; 4+ messages in thread
From: Richard Broersma Jr @ 2008-01-10 13:56 UTC (permalink / raw)
To: pgsql-sql@postgresql.org, Chinyi Woo <chinyi.woo@gmail.com>
--- On Wed, 1/9/08, Chinyi Woo <chinyi.woo@gmail.com> wrote:
> Does Postgresql support query like SELECT *TOP 3* * FROM
> Individual ? If I use ORDER BY, I have to write non-sql
> code to get the first row in the result set, which I try
> to avoid.
As you have seen, PostgreSQL's implementation of LIMIT predicate can produce the same results as TOP.
This is another way to get these results using neither TOP or Limit, but the query will probably not perform as quickly.
SELECT I1.name, ...
FROM Individual AS I1
INNER JOIN Individual AS I2
ON I1.name < I2.name
WHERE --any where criteria you might have
GROUP BY I1.name, ...
HAVING COUNT(*) < 3
ORDER BY I1.name;
Regards,
Richard Broersma Jr.
^ permalink raw reply [nested|flat] 4+ messages in thread
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2008-01-10 03:13 Support for SQL TOP clause? Chinyi Woo <chinyi.woo@gmail.com>
2008-01-10 03:19 ` Phillip Smith <phillip.smith@weatherbeeta.com.au>
2008-01-10 11:46 ` Reinoud van Leeuwen <reinoud.v@n.leeuwen.net>
2008-01-10 13:56 ` Richard Broersma Jr <rabroersma@yahoo.com>
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