Re: Cast

From: Gaetano Mendola <mendola(at)bigfoot(dot)com>
To: pgsql-novice(at)postgresql(dot)org
Subject: Re: Cast
Date: 2004-09-08 23:18:36
Message-ID: cho411$977$1@floppy.pyrenet.fr
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-novice

Eduardo Vázquez Rodríguez wrote:

> I made I mistake choosing the data types in my database I try to run a
> query that look like this
> Duration data type is varchar
>
> SELECT name, SUM(duration) AS total
> FROM table
> GROUP BY name
> HAVING name != 'John'
>
> I get the following error:
> ERROR: function sum(character varying) does not exist
> HINT: No function matches the given name and argument types. You may
> need to add explicit type casts.
>
> 1. How can I made a cast on the query from varchar to int?

Try with:

... SUM(duration::integer) ...

> 2. If I change the datatype on the database from varchar to int, do I
> loose all the data on that field?

You can create a new integer column, copy all datas from the old
VARCHAR column to the new one and with a rename column and a remove column
you finish...

Regards
Gaetano Mendola

In response to

  • Cast at 2004-09-08 21:29:26 from Eduardo Vázquez Rodríguez

Browse pgsql-novice by date

  From Date Subject
Next Message Pradeepkumar, Pyatalo (IE10) 2004-09-09 14:13:50 how to overwrite tuples in a table
Previous Message Eduardo Vázquez Rodríguez 2004-09-08 21:29:26 Cast