How to do mathematical computation in stored procedure in snowflake? - stored-procedures

Question

I am getting a count(*) after joining two Snowflake tables. This is done inside a stored procedure. If the count is greater than zero, I need to pass a value. My stored procedure gets called from a NiFi Processor and I have to return the value to NiFi so that an email can be sent from NiFi.
I am getting 'NaN' as output for the below code.
CREATE OR REPLACE PROCEDURE test_Delete_excep()
returns float not null
language javascript
as
$$
var rs;
var return_value = 0;
var SQL_JOIN = "select count(*) from (Select GT.VARIANTDATA from GOV_TEST GT inner join GOV_TEST_H GTH on GT.VARIANTDATA:COL1::String = GTH.VARIANTDATA:COL1::String where to_char(GT.VARIANTDATA) != to_char(GTH.VARIANTDATA));";
var stmt = snowflake.createStatement({sqlText: SQL_JOIN});
rs = stmt.execute();
rs.next();
return_value += JSON.stringify(rs.getColumnValue(1));
if (return_value > 0) { return 'email required';}
$$;
Here is the result:
Row TEST_DELETE_EXCEP
1 NaN
How can I do the arithmetic calculation and return a value to NiFi processor?

Answer 1

You are never returning a float value, which the SP defines as the return type. If return_value is greater than 0, it will try to return the string 'email required.', which is not a float. That will generate a NaN. If return_value is not greater than 0, the code will never return a value of any kind. That will return NULL. Since you specify NOT NULL for the return, that will force it to NaN
Also, I'm not sure why you're trying to stringify the rs.getColumnValue(1). The select count(*) will produce an integer value, which you can read directly.
You probably want something like this:
CREATE OR REPLACE PROCEDURE test_Delete_excep()
returns float not null
language javascript
as
$$
var rs;
var return_value = 0;
var SQL_JOIN = "select count(*) from (Select GT.VARIANTDATA from GOV_TEST GT inner join GOV_TEST_H GTH on GT.VARIANTDATA:COL1::String = GTH.VARIANTDATA:COL1::String where to_char(GT.VARIANTDATA) != to_char(GTH.VARIANTDATA));";
var stmt = snowflake.createStatement({sqlText: SQL_JOIN});
rs = stmt.execute();
if(rs.next()) {
return_value = rs.getColumnValue(1);
} else {
return -1;
}
return return_value;
$$;
This will return the row count produced by your join SQL. If you want something different, please clarify the desired output.