From: Pavel Stehule <pavel.stehule@gmail.com>
To: Charles O'Farrell <charleso@gmail.com>
Cc: pgsql-bugs@postgresql.org
Subject: Re: Substring auto trim
Date: Wed, 13 Jan 2010 14:36:19 +0100
Message-ID: <162867791001130536w4a14520bobc67d1c7e7e47862@mail.gmail.com> (raw)
In-Reply-To: <65d71e1c1001130102j5f46299cm87477efcfd0c5a51@mail.gmail.com>
References: <65d71e1c1001130102j5f46299cm87477efcfd0c5a51@mail.gmail.com>
Hello
2010/1/13 Charles O'Farrell <charleso@gmail.com>:
> Hi guys,
>
> I'm not sure whether this a really dumb question, but I'm curious as to what
> might be the problem.
>
> We have a column 'foo' which is of type character (not varying).
>
> select substr(foo, 1, 10) from bar
>
> The result of this query are values whose trailing spaces have been trimmed
> automatically. This causes incorrect results when comparing to a value that
> may contain trailing spaces.
>
> select * from bar where substr(foo, 1, 4) = 'AB '
>
You have to write C function substr for type "any" :( Because "char"
and char(n) are two different types, and you cannot to write function
for char(n)
> I should mention that we normally run Oracle and DB2 (and have done for many
> years), but I have been pushing for Postgres as an alternative.
> Fortunately this is all handled through Hibernate, and so for now I have
> wrapped the substr command in rpad which seems to do the trick.
>
> Any light you can shed on this issue would be much appreciated.
>
Function substr has first parameter of type "text". When pg call this
function, then it does conversion from char(x) to text.
Regards
Pavel Stehule
> Cheers,
>
> Charles O'Farrell
>
> PostgreSQL 8.4.2 on i486-pc-linux-gnu, compiled by GCC gcc-4.4.real (Ubuntu
> 4.4.1-4ubuntu8) 4.4.1, 32-bit
>
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To: pgsql-bugs@postgresql.org
Cc: pavel.stehule@gmail.com, charleso@gmail.com
Subject: Re: Substring auto trim
In-Reply-To: <162867791001130536w4a14520bobc67d1c7e7e47862@mail.gmail.com>
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