Re: syntax prob

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От Tod McQuillin
Тема Re: syntax prob
Дата
Msg-id Pine.GSO.4.31.0102240950200.13223-100000@sysadmin
обсуждение исходный текст
Ответ на syntax prob  ("postgresql" <pgsql@symcom.com>)
Список pgsql-sql
On Fri, 23 Feb 2001, postgresql wrote:

> when doing  updates of multiple fields there commas between
> the  elements?

Yes.  update t set a=b, c=d where ...

> if I could get to the server I would just try it. what happens if you have
> only 1 field to update and you add a comma, like this
>
> update table set cname = 'Bill',  where acode = 'AVAN';

You get: ERROR:  parser: parse error at or near "where"

> I am trying to concatenate an update string and I would love to not
> have to worry about the comma.

Here's what I do.  I keep a list of the things I am updating, like this,
in perl:

push(@updates, "set a=b");
push(@updates, "set c=d");
$sql = "update t " . join(", ", @updates) . " where ...";

or like this in php:

$updates[] = "set a=b";
$updates[] = "set c=d";
$sql = "update t " . implode(", ", $updates) . " where ...";

The join() and implode() functions make sure no comma is used if the
updates array has fewer than two elements.  Otherwise they stick commas
between each one, just like sql wants.
-- 
Tod McQuillin




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