Tom Lane wrote:
Brian Hurt <bhurt@janestcapital.com> writes:
I'm trying to write a generic equals operator that works on type
anyelement,
What for? You'd ultimately have to depend on the various actual input
types' native equality operators, so I don't see what this'd buy except
a layer of useless-seeming overhead. Also, it could only be hashable
if the input type's equality is hashable, and we don't have any way to
deal with a "sometimes hashable" equality operator.
regards, tom lane
What I'd like to write is:
CREATE FUNCTION eqnull(anyelement, anyelement) RETURNS BOOLEAN AS $_$
SELECT
(CASE
WHEN $1 IS NULL AND $2 IS NULL THEN TRUE
WHEN ($1 IS NULL AND $2 IS NOT NULL)
OR ($1 IS NOT NULL AND $2 IS NULL)
THEN FALSE
ELSE $1 = $2
END
)
$_$ IMMUTABLE LANGUAGE SQL;
Which changes how nulls are handled. This makes writing certain kinds of queries much easier and much more clear what the query is doing.
Am I going to need to create an operator class for every type?
Brian
