Postgres INSERT IF parameter is not null - postgresql

Question

I have a function which takes a parameter, and I want to only insert that param into a table if it's not null. I'm trying something like this:
CREATE OR REPLACE FUNCTION app.some_function(
my_param integer)
RETURNS void
LANGUAGE 'sql'
COST 100
VOLATILE
AS $BODY$
INSERT INTO app.myTable(something)
VALUES(my_param)
ON CONFLICT(something) DO
UPDATE
SET --someConflictLogic
WHERE my_param <> '' AND my_param IS NOT NULL;
$BODY$;
I was hoping the WHERE clause here would cover me, but it's not the case. When I call this function with my_param as NULL, I get:
null value in column "something" violates not-null constraint
So it looks like it's still trying to insert it. How can I correct this condition?

Answer 1

You can turn the insert ... values () into aninsert ... select` with a where clause attached:
CREATE OR REPLACE FUNCTION app.some_function(my_param integer)
RETURNS void
LANGUAGE sql
VOLATILE
AS
$BODY$
INSERT INTO app.myTable(something)
select my_param
where my_param IS NOT NULL
and my_param <> ''
ON CONFLICT(something) DO
UPDATE
SET --someConflictLogic;
$BODY$;
The where clause you used only applies to the DO UPDATE part, not the "primary" insert part.
Unrelated, but: the name of the function language is an identifier. It should be quoted.

Answer 2

You may use IF..THEN and change to plpgsql function
CREATE OR REPLACE FUNCTION app.some_function(
my_param integer)
RETURNS void
LANGUAGE plpgsql
COST 100
VOLATILE
AS $BODY$
IF NULLIF(my_param,'') IS NOT NULL THEN
INSERT INTO app.myTable(something)
VALUES(my_param)
ON CONFLICT(something) DO
UPDATE
SET --someConflictLogic;
END IF;
$BODY$;