Thread: Null parm to a function

I want to be able to pass NULL as a parameter to a function I've defined,
but I'm not allowed to do it. I believe this is a bug.

The example follows:

CREATE TABLE test_func(                     func_sun      int4, surname       varchar(30), value         int2
NOT NULL,  CONSTRAINT p01_test_func PRIMARY KEY(func_sun)
 
);

This insert works as one would expect.

INSERT INTO test_func(func_sun, surname, value)
VALUES(1234,null,99);

Now create the function that will insert rows into my table test_func.

CREATE FUNCTION insert_row(int4,varchar,int2)
RETURNS int4 AS 'INSERT INTO test_func(func_sun, surname, value)  VALUES($1,$2,$3);  SELECT 1 AS ignore;'LANGUAGE
'sql';

Now if I try to do the same thing but via my function,SELECT insert_row(1235,null,100);
I get the following errorERROR:  typeidTypeRelid: Invalid type - oid = 0

Why wont the function allow me to pass a 'null' parm?

Cheers...Gordon
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Gordon Clarke <gordonc@acenet.net.au> writes:
> Now if I try to do the same thing but via my function,
>     SELECT insert_row(1235,null,100);
> I get the following error
>     ERROR:  typeidTypeRelid: Invalid type - oid = 0

> Why wont the function allow me to pass a 'null' parm?

You're running into a longstanding shortcoming of the function-call
interface inside Postgres: there's only one NULL-parameter flag passed
to a function, so if any of the parameters are NULL then they all are
taken to be NULL.  I'm not quite sure why you're seeing that particular
error message, but in any case you'd have gotten a failure from the NOT
NULL constraints on the other two columns.

The only comfort I have to offer is that this will work in 7.1 ---
in fact, your example does work in current development sources.  
That's a result of a major rewrite of the function manager.  There's
no chance of backpatching the fix into 7.0.* or earlier.
        regards, tom lane