SSRS Report shows data for different dates - sql

Question

My report(which calculates attendance %) shows aggregated data if I remove the sessiondate field.
But I need it as users need to run it each month(currently we run query manually)
So, I have sessiondate field in my query which is based on start and end date parameters
Query:
SELECT sessiondate,
Possible,
Present,
SUM(Possible_Duration) AS Possible_Duration,
SUM(Present_Duration) AS Present_Duration,
CASE WHEN SUM(Present_Duration) = 0 THEN 0
ELSE
SUM(Present_Duration) / SUM(Possible_Duration) END AS Attendance,
SUM(CASE WHEN Mark = 'L' THEN 1 ELSE 0 END) AS Late_Mark,
SUM(Possible) AS Possib,
SUM(CASE WHEN Mark = 'A' THEN 1 ELSE 0 END) AS Authorised_absence,
SUM(CASE WHEN Mark = '/' THEN 1 ELSE 0 END) AS Present_,
SUM(CASE WHEN Mark = 'O' THEN 1 ELSE 0 END) AS Absent_fromClass
FROM Table
WHERE Sessiondate >= #startdate
AND Sessiondate <= #Enddate
GROUP BY Session_dt
Query result:
--------------------------------------
col1 | col2 | Session_dt | attendance
--------------------------------------
A | B | 01/01/2015 | 100
A | B | 03/01/2015 | 69
A | B | 05/01/2015 | 100
Expected result:
--------------------------
col1 | col2 | attendance
--------------------------
A | B | 89.3
For now I just specified dates in my query and running the report. Is there any way I can achieve this using parameter values?

Answer 1

This query will return data between first and last date of the current month, then you only need to schedule your report to run every month end or something:
select *
where [Date] between
CONVERT(VARCHAR(25),DATEADD(dd,-(DAY(GETDATE())-1),GETDATE()),101) --first date
and
CONVERT(VARCHAR(25),DATEADD(dd,-(DAY(DATEADD(mm,1,GETDATE()))),DATEADD(mm,1,GETDATE())),101) --last date

Answer 2

You can put one parameter on your SSRS report as #monthNo and simply display the month list of Jan - Dec with simply value of 1 -12.
On SQL side, you could receive month number that the user selected and use it like this:
declare #monthNo as char(2) = '1'; -- remove this from your SQL
declare #firstDate as datetime;
declare #lastDate as datetime;
select #firstDate = CONVERT(datetime,CONVERT(CHAR(4),year(getdate())) + '-' + #monthNo + '-1');
select #lastDate = dateadd(day,-1,(dateadd(month,1,#firstDate)));
select *
from [table]
where [date] between #firstDate and #lastDate;
Now you can run the report for whatever month.