Question

I have Following Tables in SQL Server Database:

(1) StudentMaster (StudentId, StudentName)

(2) SubjectMaster (SubjectId, SubjectName)

(3) AttendanceMaster (AttendanceId,StudentId,SubjectId,Attendance,Date)


Data in AttendanceMaster can be in Following format :

AttendanceMaster :
           AttendanceId   StudentId   SubjectId    Attendance   Date
              3001          33          1            P           1/1/2011 
              3001          57          2            P1          1/2/2011 
              3001          33          1            P           1/3/2011 
              3001          57          2            P2          1/4/2011 
              3001          33          1            P1          1/5/2011  

I want to get SubjectWise Individual Attendance Details in Following Format:

StudentName  SubjectName   Total(P)  Total(P1)  Total(P2)
 Ghanshyam     Maths         90        10          5
 John          Maths         85        15          5
 Ghanshyam     Science       70        20          15
 John          Science       80        30          5  

i tried following Query :

select StudentName, SubjectName,
(select count(*) from AttendanceMaster innerAM where innerAM.StudentId = StdM.StudentId and innerAM.SubjectId=SubM.SubjectId and innerAM.Attendance = 'P') as Total(P),
(select count(*) from AttendanceMaster innerAM where innerAM.StudentId = StdM.StudentId and innerAM.SubjectId=SubM.SubjectId and innerAM.Attendance = 'P1') as Total(P1),
(select count(*) from AttendanceMaster innerAM where innerAM.StudentId = StdM.StudentId and innerAM.SubjectId=SubM.SubjectId and innerAM.Attendance = 'P1') as Total(P2)
from AttendanceMaster AM inner join StudentMaster StdM on AM.StudentId = StdM.StudentId
inner join SubjectMaster SubM on AM.SubjectId = SubM.SubjectId

I got result but it gets too much time to execute..( about 5 to 6 minut )

so what can i do to decrease execution time...

and also is it right way to write a query to get Total(P),Toal(P1),Total(P2) ??
please specify other SQL Syntax

Thanks

Answer 1

Try this. If your query is still running slow, you need to check if there indexes on your table. If you table are large and there’re no indexes it still can be slow.

select
    StM.StudentName,
    SbjM.SubjectName,
    count(case when AtM.Attendance = 'P' then 1 else null end) as Total(P),
    count(case when AtM.Attendance = 'P1' then 1 else null end) as Total(P1),
    count(case when AtM.Attendance = 'P2' then 1 else null end) as Total(P2)
from StudentMaster  as StM
    inner join AttendanceMaster as AtM on AtM.StudentId = StM.StudentId
    inner join SubjectMaster as SbjM on SbjM.SubjectId = AtM.SubjectId
group by
    StM.StudentName,
    SbjM.SubjectName

If columns Attendance has no values besides P, P1 and P2, to count total you need just add count(*) as Total. If there are other values besides P, P1 and P2, there two ways. First – you can add
AtM.Attendance in (‘P’, ‘P1’, ‘P2’) in where clause:

select
    StM.StudentName,
    SbjM.SubjectName,
    count(case when AtM.Attendance = 'P' then 1 else null end) as Total(P),
    count(case when AtM.Attendance = 'P1' then 1 else null end) as Total(P1),
    count(case when AtM.Attendance = 'P2' then 1 else null end) as Total(P2),
    count(*) as Total
from StudentMaster  as StM
    inner join AttendanceMaster as AtM on AtM.StudentId = StM.StudentId
    inner join SubjectMaster as SbjM on SbjM.SubjectId = AtM.SubjectId
where AtM.Attendance in ('P', 'P1', 'P2')
group by
    StM.StudentName,
    SbjM.SubjectName

Or you can write it like this

select
    StM.StudentName,
    SbjM.SubjectName,
    count(case when AtM.Attendance = 'P' then 1 else null end) as Total(P),
    count(case when AtM.Attendance = 'P1' then 1 else null end) as Total(P1),
    count(case when AtM.Attendance = 'P2' then 1 else null end) as Total(P2),
    count(case when AtM.Attendance in ('P', 'P1', 'P2') then 1 else null) as Total
from StudentMaster  as StM
    inner join AttendanceMaster as AtM on AtM.StudentId = StM.StudentId
    inner join SubjectMaster as SbjM on SbjM.SubjectId = AtM.SubjectId
group by
    StM.StudentName,
    SbjM.SubjectName