How to display rollup data in new column? - tsql

Question

I have the following query which returns the number of android questions per each day on StackOverflow in the year of 2011. I want to get the sum of all the questions asked during the year 2011. For this I am using ROLLUP.
select
year(p.CreationDate) as [Year],
month(p.CreationDate) as [Month],
day(p.CreationDate) as [Day],
count(*) as [QuestionsAskedToday]
from Posts p
inner join PostTags pt on p.id = pt.postid
inner join Tags t on t.id = pt.tagid
where
t.tagname = 'android' and
p.CreationDate > '2011-01-01 00:00:00'
group by year(p.CreationDate), month(p.CreationDate),day(p.CreationDate)
​with rollup
order by year(p.CreationDate), month(p.CreationDate) desc,day(p.CreationDate) desc​
This is the output:
The sum of all questions asked on each day in 2011 is being displayed in the QuestionsAskedToday column itself.
Is there a way to display the rollup in a new column with an alias?
Link to the query

Answer 1

To show this as a column rather than a row you can use SUM(COUNT(*)) OVER () instead of ROLLUP. (Online Demo)
SELECT YEAR(p.CreationDate) AS [Year],
MONTH(p.CreationDate) AS [Month],
DAY(p.CreationDate) AS [Day],
COUNT(*) AS [QuestionsAskedToday],
SUM(COUNT(*)) OVER () AS [Total]
FROM Posts p
INNER JOIN PostTags pt
ON p.id = pt.postid
INNER JOIN Tags t
ON t.id = pt.tagid
WHERE t.tagname = 'android'
AND p.CreationDate > '2011-01-01 00:00:00'
GROUP BY YEAR(p.CreationDate),
MONTH(p.CreationDate),
DAY(p.CreationDate)
ORDER BY YEAR(p.CreationDate),
MONTH(p.CreationDate) DESC,
DAY(p.CreationDate) DESC

Answer 2

You could take an approach like this: Example
SELECT
YEAR(p.CreationDate) AS 'Year'
, CASE
WHEN GROUPING(MONTH(p.CreationDate)) = 0
THEN CAST(MONTH(p.CreationDate) AS VARCHAR(2))
ELSE 'Totals:'
END AS 'Month'
, CASE
WHEN GROUPING(DAY(p.CreationDate)) = 0
THEN CAST(DAY(p.CreationDate) AS VARCHAR(2))
ELSE 'Totals:'
END AS [DAY]
, CASE
WHEN GROUPING(MONTH(p.CreationDate)) = 0
AND GROUPING(DAY(p.CreationDate)) = 0
THEN COUNT(1)
END AS 'QuestionsAskedToday'
, CASE
WHEN GROUPING(MONTH(p.CreationDate)) = 1
OR GROUPING(DAY(p.CreationDate)) = 1
THEN COUNT(1)
END AS 'Totals'
FROM Posts AS p
INNER JOIN PostTags AS pt ON p.id = pt.postid
INNER JOIN Tags AS t ON t.id = pt.tagid
WHERE t.tagname = 'android'
AND p.CreationDate >= '2011-01-01'
GROUP BY ROLLUP(YEAR(p.CreationDate)
, MONTH(p.CreationDate)
, DAY(p.CreationDate))
ORDER BY YEAR(p.CreationDate)
, MONTH(p.CreationDate) DESC
, DAY(p.CreationDate) DESC​​​​​​​
If this is what you wanted, the same technique can be applied to Years as well to total them in the new column, or their own column, if you want to query for multiple years and aggregate them.