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 | | From: | Joost Kraaijeveld | | Subject: | plpgsql howto question | | Date: | Thu, 23 Dec 2004 15:19:54 +0100 |
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 | Hi all,
I want to use a plpgsql function that returns the value of a column, depending on the arguments ( the code below does not work, hence the question):
CREATE OR REPLACE FUNCTION getcustomername(text, int4)
RETURNS text AS
'
BEGIN
IF $2 = 1 THEN
SELECT lastname FROM person WHERE objectid = $1;
RETURN lastname;
ELSIF $2 = 2 THEN
SELECT name into name1 from company WHERE objectid = $1;
RETURN name1;
END IF;
END
' LANGUAGE 'plpgsql' VOLATILE;
What is the correct way of doing this?
TIA
Groeten,
Joost Kraaijeveld
Askesis B.V.
Molukkenstraat 14
6524NB Nijmegen
tel: 024-3888063 / 06-51855277
fax: 024-3608416
e-mail: J.Kraaijeveld@Askesis.nl
web: www.askesis.nl
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| | From: | Frank van Vugt | | Subject: | Re: plpgsql howto question | | Date: | Thu, 23 Dec 2004 16:27:20 +0100 |
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| Hi Joost,
> What is the correct way of doing this?
As 'always', there's more than one way of doing this, for example
- selecting into a var and returning that var
- selecting into a record and returning the proper field of that record
- return the proper values immediately
- use 'plain' sql in combination with a case statement
Some examples:
CREATE OR REPLACE FUNCTION getcustomername(text, int4)
RETURNS text AS
'
DECLARE
my_person TEXT;
my_company RECORD;
BEGIN
IF $2 = 1 THEN
SELECT INTO my_person lastname FROM person WHERE objectid = $1;
RETURN my_person;
ELSIF $2 = 2 THEN
SELECT INTO my_company name1 from company WHERE objectid = $1;
RETURN my_company.name1;
END IF;
END
' LANGUAGE 'plpgsql' VOLATILE;
*****
CREATE OR REPLACE FUNCTION getcustomername(text, int4)
RETURNS text AS
'
DECLARE
my_id ALIAS FOR $1;
my_type ALIAS FOR $2;
BEGIN
IF my_type = 1 THEN
RETURN my_person lastname FROM person WHERE objectid = my_id;
ELSIF my_type = 2 THEN
RETURN name1 from company WHERE objectid = my_id;
END IF;
END
' LANGUAGE 'plpgsql' VOLATILE;
*****
SELECT CASE
WHEN type = 1 THEN (SELECT person)
WHEN type = 2 THEN (SELECT company)
ELSE null
END;
(albeit this is not plpgsql anymore)
Obviously you want to choose one of the approaches ;)
NB. Prettige kerstdagen alvast !
--
Best,
Frank.
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