Function with DEFAULT arguments
От | dario.ber@libero.it |
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Тема | Function with DEFAULT arguments |
Дата | |
Msg-id | 32871558.187291268411337102.JavaMail.defaultUser@defaultHost обсуждение исходный текст |
Ответы |
Re: Function with DEFAULT arguments
Re: Function with DEFAULT arguments |
Список | pgsql-general |
Hello, I'm trying to use the DEFAULT option to pass parameters to the arguments of a function. When I call that function, how can I change the default value of some arguments and leave as default the value of other arguments? In other words, is there a way to 'call' the arguments by their names so to specify which should have their default value changed? Here's a toy example, a function that takes three strings as arguments and concatenate them: CREATE FUNCTION test_default(string1 text default 'a', string2 text default 'b', string3 text default 'c') RETURNS text AS $$ BEGIN RETURN string1 || string2 || string3; END; $$ language 'plpgsql'; -- Only default args: SELECT test_default(); --> abc -- With custom values: SELECT test_default('X', 'Y', 'Z'); --> XYZ -- Now, how can I leave as default the 1st and 3rd argument (string1 and string3) and change only the second one (string2)? I would like to do something like: SELECT test_default(string2= 'Y'); -- To return 'aYb' And in general, are there any examples/documentation that show how to use the option default? I'm using postgresql 8.4.2 on Windows XP. Many thanks Dario
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