Re: PG SQL and LIKE clause - Mailing list pgsql-general

From John W Higgins
Subject Re: PG SQL and LIKE clause
Date
Msg-id CAPhAwGzoetKLkpCQd8M8Wx22N-DS+OEh-FsaCDNAMgesnN4=Jw@mail.gmail.com
Whole thread Raw
In response to PG SQL and LIKE clause  (Matthias Apitz <guru@unixarea.de>)
List pgsql-general
Is this a possibility?

From https://www.postgresql.org/docs/current/functions-matching.html#FUNCTIONS-POSIX-REGEXP -

~ 'ali[ ]*$' matches strings ending in ali that have zero of more spaces after ali

this would match

'bali'
'ali'
'ali '
'bali '

If you need full string then it would be like this

~ '^ali[ ]*$' matches string only containing ali plus zero or more spaces after ali

this would match

'ali'
'ali '

but not match

'bali'
'bali '

Also switching ~* for ~ makes if case insensitive if necessary.


John


On Thu, Sep 12, 2019 at 10:29 PM Matthias Apitz <guru@unixarea.de> wrote:

Hello,

We're porting a huge Library Management System, written using all kind
of languages one can think of (C, C++, ESQL/C, Perl, Java, ...) on Linux
from the DBS Sybase to PG, millions of lines of code, which works also
with DBS Oracle and in the past with INFORMIX-SE and -ONLINE.

We got to know that in CHAR columns with trailing blanks a

SELECT ... FROM ... WHERE name LIKE 'Ali'

does not match in 'name' having 'Ali '.

I glanced through our code with grep pipelines and found some hundred
places which would be affected by this problem. I'm not interested in a
religious discussion if or if not this behaviour of PG is correcter or
better than in Sybase. It's just different to Sybase.

Any hints to address this problem? Or is there any compile time option
for the PG server to address this?

Thanks

        matthias
--
Matthias Apitz, ✉ guru@unixarea.de, http://www.unixarea.de/ +49-176-38902045
Public GnuPG key: http://www.unixarea.de/key.pub

Mientras haya voluntad de lucha habrá esperanza de vencer.


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