Hi,

Is there a way to raise an exception with a message,
without having to add your own plpgsql helper-function?

Currently this is what I have:

CREATE OR REPLACE FUNCTION raise(message text, debug json, dummy_return_value 
anyelement)
RETURNS anyelement
LANGUAGE plpgsql
AS $$
BEGIN
RAISE '% %', message, debug;
END;
$$;

The dummy value allows using the function in a context where a value of the 
given type is expected.

Here is a mockup example on the coding pattern where I typically would use this 
raise() helper-function:

SELECT
  CASE
    WHEN foo = 0 THEN f0(bar)::baz
    WHEN foo = 1 THEN f1(bar)::baz
    WHEN foo = 2 THEN f2(bar)::baz
    ELSE raise('Not implemented',json_build_object(
    'foo',foo,
    'bar',bar
    ),NULL::baz)
  END
FROM ...

The idea is to throw an exception when a case is not handled, instead of just 
letting the CASE produce a NULL value.

The dummy_return_value anyelement with the same type as the other CASEs is 
necessary, otherwise, if trying to just return anyelement without the 
dummy_return_value you would get error:

DETAIL:  A result of type anyelement requires at least one input of type 
anyelement, anyarray, anynonarray, anyenum, or anyrange.

Is there any idiomatic way of achieving the same, without having to rely on a 
plpgsql function in this way?

Best regards,

Joel

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