Re: Porting Oracle Decode to Postgresql

Dear Tod McQuillin,
  Can perform the action as same as oracle in
postgresql ? 
  e.g.  Select decode_function( ... , ... , ..... ) from ..

  I can write a plpgsql to simulate the nvl function
by using coalesce .

CREATE FUNCTION nvl( numeric, numeric ) RETURNS
varchar AS '
DECLARE  input_value  ALIAS FOR $1;  else_value   ALIAS FOR $2;  output_value numeric;
BEGIN  select coalesce( input_value, else_value ) into
output_value ;  return output_value ;
END;   
' LANGUAGE 'plpgsql' ;

M.T.


--- Tod McQuillin <devin@spamcop.net> wrote:
> On Thu, 22 Nov 2001, MindTerm wrote:
> 
> >   I am writing to ask how to port oracle's decode(
> ..)
> > function to postgresql ?
> 
> The ANSI SQL version of decode is CASE.
> 
> See
>
http://www.postgresql.org/idocs/index.php?functions-conditional.html
> for the full documentation, but basically, it works
> like this:
> 
> Oracle:
> decode (value, 0, 'zero', 1, 'one', 'unknown')
> 
> ANSI:
> CASE WHEN value=0 THEN 'zero' WHEN value=1 THEN
> 'one' ELSE 'unknown' END
> 
> or
> 
> CASE value WHEN 0 THEN 'zero' WHEN 1 THEN 'one' ELSE
> 'unknown' END
> 
> -- 
> Tod McQuillin
> 
> 


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