Oracle SQL-简化总计列

Question

I have the below issues that I would like to address:

1. Is there a way to simplify the Total column?
2. The bottom row reads as null, I would like that to be "Total" as well.
3. Is it better to ROLLUP the way I have it, ROLLUP((status))? Or this is exactly same as ROLLUP(status)?

Below is my query:

SELECT
        status AS "ROW LABELS",
        COUNT(case when source = 'INTERNET' THEN 1 end) AS "INTERNET",
        COUNT(case when source = 'SALES' THEN 1 end) AS "SALES",
        COUNT(case when source = 'REP' THEN 1 end) AS "REP",
        COUNT(case when source = 'COM' THEN 1 end) AS "COM",
        (COUNT(case when source = 'INTERNET' THEN 1 end) +
        COUNT(case when source = 'SALES' THEN 1 end) +
        COUNT(case when source = 'REP' THEN 1 end) +
        COUNT(case when source = 'COM' THEN 1 end)
        ) AS Total
FROM
SOMETABLE
GROUP BY ROLLUP((status))
order by 1;

Below is my data:

Answer 1

1. If by "simplify" you mean "make the calculation more succinct", then yes. The following will work:

    COUNT(CASE WHEN source IN ('INTERNET', 'SALES', 'REP', 'COM') THEN 1 END) 

2. Simply use nvl to convert the NULL to a value: NVL(status, 'TOTAL') AS row_labels

3. ROLLUP( (status) ) is the same as ROLLUP( status )