How to use results of [with totals] modifier - clickhouse

Question

We have modifier [with totals] that can summarize values across all rows and get the total result with key value=0 or null or smth like this
The problem is that I don't understand how I can use these values in the next calculations
Maybe I'm using the wrong format
select processing_date,count(*)
from `telegram.message`
where processing_date>='2019-05-01'
group by processing_date with totals

Answer 1

The documentation says that
You can use WITH TOTALS in subqueries, including subqueries in the
JOIN clause (in this case, the respective total values are combined).
Example subqueries in the JOIN (CH tests scripts in github):
SELECT k, s1, s2
FROM
(
SELECT intDiv(number, 3) AS k, sum(number) AS s1
FROM
(
SELECT *
FROM system.numbers
LIMIT 10
)
GROUP BY k WITH TOTALS
)
ANY LEFT JOIN
(
SELECT intDiv(number, 4) AS k, sum(number) AS s2
FROM
(
SELECT *
FROM system.numbers
LIMIT 10
)
GROUP BY k WITH TOTALS
) USING (k)
ORDER BY k ASC
/* Result:
┌─k─┬─s1─┬─s2─┐
│ 0 │ 3 │ 6 │
│ 1 │ 12 │ 22 │
│ 2 │ 21 │ 17 │
│ 3 │ 9 │ 0 │
└───┴────┴────┘
Totals:
┌─k─┬─s1─┬─s2─┐
│ 0 │ 45 │ 45 │
└───┴────┴────┘
*/
As a workaround, you can combine results of several totals using client libraries.

Answer 2

Using "with rollup" instead of "with totals" decides problems with format