Re: nvl() function

On Tue, 16 Oct 2001, Steven Dahlin wrote:

> I am trying to find the equivalent in Postgresql to the Oracle sql function
> nvl().  With nvl() you give two parameters.  The first may be a field/column
> or variable.  If the value is not null then it is returned by the function.
> For example the with query below if the :ClientParameter is passed then only
> those rows which have a clientdesc matching the parameter are returned.  If
> the :ClientParameter is null then those rows which have clientdesc =
> clientdesc are returned (all rows):
>
> select        clientid,
>                  clientdesc
>  from         clients
>  where       ( clientdesc     = nvl( :ClientParameter, clientdesc ) )
>
> I have looked thru all the documentation I could find but nowhere were any
> built-in SQL functions delineated.  Does anyone know where the documentation
> can be found?

COALESCE is the SQL standard name for this. You'll find details in the
documentation, in the Conditional Expressions section (4.10). Copy at:

http://candle.pha.pa.us/main/writings/pgsql/sgml/functions-conditional.html

-- 

Joel BURTON  |  joel@joelburton.com  |  joelburton.com  |  aim: wjoelburton
Independent Knowledge Management Consultant