Executing part of stored procedure based on condition - snowflake-cloud-data-platform

Question

I am trying to load to a table based on load types - Full or Incremental that is being passed as parameter in stored procedure. I was able to try with substitution variable with one line of code previously, but the below code doesn't seem to work -
Stored procedure possible arguments:
LOAD_TYPE=FULL
LOAD_TYPE=INCR
var incr_condition = (load_type=='INCR')?"INNER JOIN temp_table"
with temp_table(
select data
from table a
where dt between 01-01-2019 and 09-09-2020
)
select *
from table b
${incr_condition} -- execute only if load_type=INCR
INNER JOIN TABLE C ON B.ID = C.ID
Is there any way to restrict the with clause to execute only if the load_type==INCR? Please advice.

Answer 1

I think the conditional operator (question mark) must have a false part in addition to the true part. Otherwise, it generates a syntax error when there's a semicolon ending the line. This example obviously doesn't run anything, but it will return the values assigned to the "out" variable, which would be run.
Since you're using a replacement variable ${incr_condition} be sure to use backticks to open and close your SQL string.
create or replace procedure foo(LOAD_TYP string)
returns string
language javascript
as
$$
var load_type = LOAD_TYP;
var incr_condition = (load_type === 'INCR') ? "INNER JOIN temp_table" : "";
var out = `
with temp_table(
select data
from table a
where dt between 01-01-2019 and 09-09-2020
)
select *
from table b
${incr_condition} -- execute only if load_type=INCR
INNER JOIN TABLE C ON B.ID = C.ID
`;
return out;
$$;
call foo('INCR'); --Adds the inner join
call foo('FULL'); --Does not add the inner join
I also recommend changing your comparison on strings from == to ===. For details on why, reference What is the correct way to check for string equality in JavaScript?.