Thread: can't cast char to in

I have a table with a mileage column that is a character varying (please don't ask why :).

I need to do a query where mileage > 500

select * from cars where mileage>500

So I need to cast it but everything I try throws an error such as :

ERROR:  invalid input syntax for integer: "+"

How can I cast this?



Thanks!

On Apr 22, 2008, at 10:34 AM, blackwater dev wrote:

> I have a table with a mileage column that is a character varying
> (please don't ask why :).
>
> I need to do a query where mileage > 500
>
> select * from cars where mileage>500
>
> So I need to cast it but everything I try throws an error such as :
>
> ERROR:  invalid input syntax for integer: "+"
>
> How can I cast this?

Well, you didn't really give any real information on the format of the
data in your mileage column.  However, my guess is that you've got at
least one row with just '+' in the mileage column which is not the
same thing as '+0'.  You'll probably need to do a little data cleaning
and, once that's done you should definitely consider switching that to
an integer/numeric data type.

Erik Jones

DBA | Emma®
erik@myemma.com
800.595.4401 or 615.292.5888
615.292.0777 (fax)

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Yeah, it was my being stupid, I got it going now.

Thanks!

blackwater dev wrote:
> I have a table with a mileage column that is a character varying (please
> don't ask why :).

Why? :-)

> I need to do a query where mileage > 500
>
> select * from cars where mileage>500
>
> So I need to cast it but everything I try throws an error such as :
>
> ERROR:  invalid input syntax for integer: "+"

Once you've cleaned your data, I would do one of two things:

1. Add a constraint to restrict the values the mileage column will accept:
ALTER TABLE cars ADD CONSTRAINT valid_mileage
CHECK (mileage ~ '^[+]?[0-9]+$');

2. You can alter the type on-the-fly too:
ALTER TABLE mileage_test ALTER COLUMN mileage TYPE integer
USING (mileage::int);

Note that you'll need to remove the constraint from #1 if you've applied
that.

--
   Richard Huxton
   Archonet Ltd