Postgres 14

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CREATE TABLE statement(
  statement text
, is_true bool
);

INSERT INTO statement(statement, is_true)
VALUES
  ('Blue is green.', FALSE)
, ('Postgres is cool.', TRUE)
, ('Sun shines tomorrow.', NULL);
3 rows affected

CREATE FUNCTION f_oracle(is_true boolean = TRUE)  -- correct use of "=" (!)
  RETURNS text
  LANGUAGE sql AS
$func$
SELECT CASE $1
         WHEN TRUE  THEN 'That''s true.'
         WHEN FALSE THEN 'That''s false.'
         ELSE 'How should I know?'
       END
$func$;
SELECT *
     , f_oracle(is_true := is_true) AS good_oracle
     , f_oracle(is_true  = is_true) AS bad_oracle  -- incorrect use of "=" (!!!)
FROM   statement;


statement
is_true
good_oracle
bad_oracle


Blue is green.
f
That's false.
That's true.

Postgres is cool.
t
That's true.
That's true.

Sun shines tomorrow.
null
How should I know?
How should I know?

statement	is_true	good_oracle	bad_oracle
Blue is green.	f	That's false.	That's true.
Postgres is cool.	t	That's true.	That's true.
Sun shines tomorrow.	null	How should I know?	How should I know?