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Re: Support for SQL TOP clause?

From: Richard Broersma Jr <rabroersma(at)yahoo(dot)com>
To: pgsql-sql(at)postgresql(dot)org, Chinyi Woo <chinyi(dot)woo(at)gmail(dot)com>
Subject: Re: Support for SQL TOP clause?
Date: 2008-01-10 13:56:44
Message-ID: 554372.7292.qm@web31811.mail.mud.yahoo.com (view raw or flat)
Thread:
Lists: pgsql-sql
--- On Wed, 1/9/08, Chinyi Woo <chinyi(dot)woo(at)gmail(dot)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.

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