Snowflake Stored Procedure check if a variable is Null - snowflake-cloud-data-platform

Question

How to check if a variable in snowflake stored procedure is null or not. I am using snowflake scripting.
My Code:
begin
select id into :id from REQUEST where id = 1;
if(id = null) then
return 0;

Answer 1

The syntax for branch construct:
BEGIN
-- ...
IF (id IS NULL) THEN
RETURN 0;
END IF;
END;
It is also possible to use COALESCE if it is just a return statement:
BEGIN
-- ...
RETURN COALESCE(id, 0);
END;

Answer 2

Tried to cover the bases here, primarily when you have no results from the query as well as when the actual result is a NULL returned value.
--
-- create test table
--
CREATE or replace TABLE REQUEST (id integer, val INTEGER);
INSERT INTO REQUEST VALUES (1,1),(2,null),(3,3);
--
-- create test proc using SQL Script
--
CREATE OR REPLACE PROCEDURE TEST_NULLS(input integer)
returns INTEGER
LANGUAGE SQL
AS
DECLARE
val INTEGER;
rc INTEGER;
input_id INTEGER;
BEGIN
input_id := input;
-- get the row count to determine if the query criteria produces a result
SELECT count(*) into :rc
FROM REQUEST
WHERE id = :input_id;
-- if empty result set, return 0.
IF (rc = 0) then return (rc);
ELSE
-- otherwise, return the value retrieved from the query, unless it is NULL in which case return -1
SELECT nvl(val,-1) into :val
FROM REQUEST where id = :input_id;
return (val);
END IF;
END;
--
-- Test examples
--
call test_nulls(1); -- Returns 1
call test_nulls(2); -- Returns -1, since returned value is NULL
call test_nulls(3); -- Returns 3
call test_nulls(4); -- Returns 0, since there is no result set