Question

I’m using SQL Server 2005 and asp.net 2008 with c#…I have 2 tables Result and Stud_Info…….

1] Stud_Info

CREATE TABLE Stud_Info
(Enroll_Number varchar(20) NOT NULL,  
Salutation varchar(10) NULL,  
First_Name varchar(20) NULL,  
Middle_Name varchar(20) NULL,  
Last_Name varchar(20) NULL,  
Course_Id varchar(20) NULL,  
Batch varchar(20) NULL)

INSERT into Stud_Info values(11161,'Mr.','Mack','B','Botha','MECH','Batch1');    
INSERT into Stud_Info values(11162,'Mr.','John','A','Los','CIVIL','Batch2');    
INSERT into Stud_Info values(11163,'Ms.','Merry','F','Dsuza','ELCT','Batch1');    
INSERT into Stud_Info values(11164,'Mr.','Pow','B','Janero','MECH','Batch2');    
INSERT into Stud_Info values(11165,'Mr.','Martin','J','Smith','MECH','Batch1');    

SELECT * from Stud_Info  

2nd Table is like this…

2] Exam_Result

CREATE TABLE Exam_Result
(Result_Id numeric(18, 0) IDENTITY(1,1) NOT NULL,  
Enroll_Number varchar(50) NULL,  
Student_Name varchar(100) NULL,  
Course_Id varchar(50) NULL,  
Semester varchar(50) NULL,  
Subject_Id varchar(50) NULL,  
Subject_Name varchar(50) NULL,  
MarksObtained numeric(18, 0) NULL,  
Exam_Type varchar(50) NULL)

INSERT into Exam_Result values(11161,'Mack B Botha','MECH',1,'MT','Maths',25,'Internal1');  
INSERT into Exam_Result values(11161,'Mack B Botha','MECH',1,'EN','English',22,'Internal1');  
INSERT into Exam_Result values(11161,'Mack B Botha','MECH',1,'SC','Science',20,'Internal1');  
INSERT into Exam_Result values(11166,'Barden V John','CIVIL',1,'SS','Social',21,'Internal2');  
INSERT into Exam_Result values(11161,'Mack B Botha','MECH',2,'SM','Simple Maths',24,'Internal2');  
INSERT into Exam_Result values(11161,'Mack B Botha','MECH',2,'SM','Simple Maths',69,'Final');  

SELECT * from Exam_Result

I’m Using this stored procedure for dynamic transforming rows-to-columns for Subjects……and it works fine.

    Create Proc GetExamResults (@Course_Id varchar(100), @Semester varchar(10))
as
begin
    declare @subjname varchar(100)  
    declare @subjects varchar(7000)  
    declare @subjectsselection varchar(7000)  
    declare @SumSelection varchar(7000)  
    declare @NoOfSubjects int
    set @NoOfSubjects = 0

    set @subjects = ''  
    set @subjectsselection = '' 
    set @SumSelection = ''

    DECLARE subject_cursor CURSOR  
    FOR SELECT distinct Subject_Name FROM Exam_Result where course_id = @Course_Id And Semester = @Semester 

    OPEN subject_cursor  

    FETCH NEXT FROM subject_cursor  
    INTO @subjname  

    WHILE @@FETCH_STATUS = 0  
    BEGIN  
        set @subjects = @subjects + '[' + @subjname + '],'  
        set @subjectsselection = @subjectsselection + 'Sum(Isnull([' + @subjname + '],0)) As [' + @subjname + '],' 
        set @SumSelection = @SumSelection + 'Sum(Isnull([' + @subjname + '],0))+' 

        set @NoOfSubjects = @NoOfSubjects + 1

        FETCH NEXT FROM subject_cursor  
        INTO @subjname  
    End  
    CLOSE subject_cursor;  
    DEALLOCATE subject_cursor;  

    select @subjects = LEFT(@subjects, LEN(@subjects) - 1)  
    select @subjectsselection = LEFT(@subjectsselection, LEN(@subjectsselection) - 1)  
    select @SumSelection = LEFT(@SumSelection, LEN(@SumSelection) - 1)  

    print @subjects  
    print @subjectsselection  
    print @SumSelection

    declare @query nvarchar(4000)  

    set @query = 'select S.Enroll_Number, pvt.Student_Name, pvt.Course_Id, pvt.Semester, ' + @subjectsselection + ',' 
    set @query = @query + 'Exam_Type,' + @SumSelection + ' As Grand_Total, '
    set @query = @query + '(' + @SumSelection + ')' + '/' + convert(varchar(10),@NoOfSubjects) + ' As Avg'
    set @query = @query + ' From '  
    set @query = @query + '(select Enroll_Number, Student_Name, Course_Id, Semester, Subject_Name, MarksObtained, Exam_Type from Exam_Result ) ps '  
    set @query = @query + ' pivot(sum(MarksObtained) for Subject_Name in (' + @subjects + ')) as pvt'  
    set @query = @query + ' inner join Stud_Info S on S.Enroll_Number = pvt.Enroll_Number '
    set @query = @query + ' where pvt.Course_Id = ''' + @Course_Id + ''' and pvt.Semester = ''' + @Semester + ''''
    set @query = @query + ' group by S.Enroll_Number, pvt.Student_Name, pvt.Course_Id, pvt.Semester, Exam_Type'
    print @query
    exec sp_executesql @query  
end

Currently i’m getting o/p like….

Enroll_Number  Student_Name Course_Id   Semester  Maths    English    Science    Social    Smathas    total    avg

11161           MACK         MECH        1         25       22         20         0         0          67      total/all sub
11166           Barden       CIV         1         0        0          0          21        0          21      total/all sub

NOTE

here i’m getting all subjects that are in Exam_Result Table and sum of all sub (in ge you can see – 67) and avg of all subjects from Exam_Result

NOW QUESTION IS I WANT TO DISPLAY RESULTS BY GROPING AS PER USER CHOICE…. for eg if user wants to see only Course_Id = MECH and
Semester = 1….o/p should be….

Enroll_No    Student_Name    Course_ID    Semester    Maths    English    Science     Type         Grand_Total    Avg

11161        Mack B Botha     MECH         1          25        22         20        internal1       67          66.22

There is no fix no of subjects in every course and semester..it might be change….and needs to be group by Course_Id and Semester Give me guidance and query so i will implement your answer….I hope this information is enough to explain my stuff….all answers are most welcome…thanks

Answer 1

Answering this comment of yours:

its not working in sql server 2005 for my site it give error Msg 102, Level 15, State 1, Line 1 Incorrect syntax near ‘ps’. and Invalid length parameter passed to the SUBSTRING function.

The first error probably occurs when your dynamic query is executed. I can’t be sure but it looks as if the compatibility level of your database is lower than 90 and thus PIVOT is not allowed/recognised. Search this site for questions on how to pivot without the PIVOT clause to work around it. Or set your DB’s compatibility level to 90, if possible.

As for the second error, I encountered it too when I was testing your query. (It happened when I didn’t specify values for the parameters.) The source of the error is this line:

select @subjects = LEFT(@subjects, LEN(@subjects) - 1)

If the cursor query doesn’t return rows, your @subjects variable remains empty and LEN(@subjects) - 1 results in -1, which, when passed as the length argument to LEFT(), produces the error.

Simply add a condition to avoid the issue:

if LEN(@subjects) > 0 select @subjects = LEFT(@subjects, LEN(@subjects) - 1)

Do the same for the other two strings (@subjectsselection and @SumSelection).

_{And please, next time you are asking a question and saying that something is not working, make sure you put all the relevant information (including error messages) into your question, not into a comment.}