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Converting between varchar and float when updating

From: Thomas Larsen Wessel <mrvelle(at)gmail(dot)com>
To: pgsql-general(at)postgresql(dot)org
Subject: Converting between varchar and float when updating
Date: 2011-04-28 09:26:46
Message-ID: BANLkTi=aB3wgGOrVBnn7TVM8MouidrjQGg@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-general
I have a table with the following schema:
CREATE TABLE foo (bar VARCHAR(32));

Every bar value has a format like a float, e.g. "2.5". Now I want that value
multiplied by two and saved again as varchar. I was hoping to do smth like:

UPDATE foo SET bar = TO_VARCHAR( TO_FLOAT(bar) * 2); -- INCORRECT!!!!

How is that done?

I know that the bar attribute ought to have type FLOAT, but I have to work
with this legacy database. And anyway this table will rarely be updated.

Sincerely, Thomas

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Next:From: Dmitriy IgrishinDate: 2011-04-28 09:40:40
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