UPDATE admin
SET parent = SUBSTR(id,1,4);
Doesn't it do what you want?
Best,
Oliveiros
----- Original Message -----
From: "ssylla" <stefansylla@gmx.de>
To: <pgsql-sql@postgresql.org>
Sent: Thursday, February 09, 2012 1:58 AM
Subject: [SQL] update column
> Dear list,
>
> sorry, I already posted this, but it did not seem to have been accepted by
> the mailing list. So here's my second try:
>
> I need to update all rows of a column ('parent') based on a subquery that
> returns me the first four digits of another column ('id'):
>
> UPDATE admin SET parent=(SELECT SUBSTR(id,1,4) FROM admin);
>
>
> After executing, I get the following error-message:
>
> "more than one row returned by a subquery used as an expressionmore than
> one
> row returned by a subquery used as an expression"
>
>
> I am not quite sure about that, but maybe I need to construct a
> function/loop to fulfill this task?
>
> thanks for help.
>
> Stefan
>
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