I noticed this one by searching in the archives, as I am working with some “optional” parameters myself and noticed your solution. I just wanted to make one improvement suggestion which is instead of checking whether or not a parameter has been used simply start your query like so
Query_base := ‘SELECT * FROM my_table WHERE 1 =1;
If you do that then you can just add on any parameters you need or not add any at all. I think that seems to be a bit simpler than having a “has_param” Boolean variable.
Thanks,
Curtis
From: Rob Tester [mailto:robtester@gmail.com]
Sent: Thursday, August 17, 2006 8:58 PM
To: MaXX
Cc: pgsql-sql@postgresql.org
Subject: Re: [SQL] Help with optional parameters
BEGIN
query_base := 'SELECT * FROM my_table ';
has_param := FALSE;
query_where := '';
IF (a IS NOT NULL) THEN
IF (has_param IS FALSE)THEN
-- there is no param yet add WHERE to the query
query_where := ' WHERE ';
ELSE
-- there is already something in the WHERE clause, we need to add AND
query_where := query_where || ' AND ';
END IF;
query_where := query_where || 'parama='||a;
--beware if param quoting is required
has_param := TRUE; -- now there is at least 1 param
END IF;