From: "Bill" <bchie@opensys.com.hk>
Subject: Re: DateDiff, IsNull?
Date: Wed, 15 Aug 2001 11:44:01 +0800
Organization: Hub.Org Networking Services (http://www.hub.org)
Lines: 45
Message-ID: <9lcrih$15lk$1@news.tht.net>
References: <web-101872@davinci.ethosmedia.com>
To: pgsql-sql@postgresql.org

> Bill,
>
> >   I am a newbie to postgreSQL, is it possible to write a "DateDiff",
> > "IsNull" function work same as the one in SQL Server and are there
> > and
> > sample out there?
>
> I take it that you want to do this to port an exisiting application?
>
> If so, the DateDiff thing has already been covered in Roberto Mello's
> "cookbook".
>
> However, ISNULL, last I checked, was a Microsoft Access function and not
> supported by MS SQL Server.  If you're porting from MS Access, you'll
> need to fix a lot more of your SQL than the functions.  There is,
> however, help for MS Access users:
> (for both of the above)
> http://techdocs.postgresql.org/
  I need to port a application that run on MS SQL Server/
Sybase SQL Anyway to postgreSQL, the 2 function list
about is the one used most in the application
  I don't know when MS SQL Server being to have the funtion
IsNull, but it exist from ver. 6.5 and up, and the syntax is
IsNull( field_name, default_value), and will return the
default_value when field is null

> > And is it possible to override the existing
> > function and
> > operator like "+" to become a concate?
>
> How's your C porgramming?  It's an open-source database, you can do
> anything for which you have the skill and the time.  The advisability of
> doing so, however, is another thing entirely ...
>
> Given that all of the MS SQL Server "peculiarities" are not ANSI SQL
> standard, have you given any thought to porting by search-and-replace
> script instead of trying to make Postgres support a bunch of
> non-standard operators and functions?  It'd be easier.
  Yup, I also think it is easier, but it is an order

Thanks for your help

Bill