Re: = or := ?

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От Zlatko Matic
Тема Re: = or := ?
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Msg-id 006301c554b3$cee15440$48778353@zlatkovyfkpgz6
обсуждение исходный текст
Ответ на Connecting to Postgres using Rekall  (Susemail <susemail@hawaii.rr.com>)
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thanks.
----- Original Message -----
From: "Michael Glaesemann" <grzm@myrealbox.com>
To: "Zlatko Matic" <zlatko.matic1@sb.t-com.hr>
Cc: <pgsql-general@postgresql.org>
Sent: Monday, May 09, 2005 11:30 AM
Subject: Re: [GENERAL] = or := ?


>
>
> On May 9, 2005, at 18:00, Zlatko Matic wrote:
>
>> This is a newbie question: what is the difference between using = and
>> := in plpgsql function ?
>
> In pl/pgsql,
>
> := is assignment
> = is a logical comparison for equality
>
> Some languages, such as perl, use = for assignment and == for logical
> comparison.
>
> x = 1
> is a boolean result
>
> x := 1
> gives x the value of 1
>
> Quick example:
>
> x := 2; -- gives x the value of 2
>
> IF (x = 1) THEN -- x = 1 is false
> x := 3;  -- skipped
> END IF;
> RETURN X; -- returns 2
>
> Again:
> x := 1; -- gives x the value of 1
>
> IF (x = 1) THEN -- x = 1 is true
> x := 3;  -- perform assignment
> END IF;
> RETURN x; -- returns 3
>
> Hope this helps.
>
> Michael Glaesemann
> grzm myrealbox com
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org
>

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