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Looking to pivot grades table

Posted on 2013-06-24
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Last Modified: 2014-01-13
I have a table that stores student grades:
StudentID
CourseCode
CourseName
TermCode
TeacherName
GradeEarned

A student could be given multiple grades for the same course throughout the year with the TermCode being the key.

I'd like to have a SQL statement that pivots this table and returns the data horizontally like a gradebook view:
StudentID----CourseName---TeacherName----Q1--Q2--Q3--Q4
123435          AlgebraI            Mr. Smith            A     B+   B     A-
123435          History              Mr. Jones             C     C+   B-    B

The list of possible TermCodes is known so that doesn't need to be dynamic and I do only need to return the four columns of potential term grades.

js
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Question by:jswanberg
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6 Comments
 
LVL 49

Assisted Solution

by:PortletPaul
PortletPaul earned 1000 total points
ID: 39270569
select
  StudentID
--, CourseCode
, CourseName
, max(case when TermCode = 'Q1' then GradeEarned end) as Q1
, max(case when TermCode = 'Q2' then GradeEarned end) as Q2
, max(case when TermCode = 'Q3' then GradeEarned end) as Q3
, max(case when TermCode = 'Q4' then GradeEarned end) as Q4
from YourTable
group by
  StudentID
--, CourseCode
, CourseName

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LVL 49

Expert Comment

by:PortletPaul
ID: 39270574
this is a "classic pivot" using case when syntax. As your TermCode's are a known list, and you only require 4 grade columns, this seems completely appropriate.

Note, sometimes there is a concern about using MAX(...) to achieve these pivots, but it should not be an issue - provided there is only one grade given per student/course/term

The use of MAX() in such a scenario really just allows for reduction from multiple rows to a single row.
0
 
LVL 11

Expert Comment

by:Louis01
ID: 39270891
--Prepare sample table
declare @theTable table(  StudentID int
						, CourseName varchar(50)
						, TermCode char(2)
						, GradeEarned varchar(2));

insert into @theTable (StudentID, CourseName, TermCode, GradeEarned) values (1, 'Course 1', 'Q1', 'A');
insert into @theTable (StudentID, CourseName, TermCode, GradeEarned) values (1, 'Course 2', 'Q1', 'B');
insert into @theTable (StudentID, CourseName, TermCode, GradeEarned) values (1, 'Course 1', 'Q1', 'C');
insert into @theTable (StudentID, CourseName, TermCode, GradeEarned) values (1, 'Course 2', 'Q1', 'D');
insert into @theTable (StudentID, CourseName, TermCode, GradeEarned) values (2, 'Course 1', 'Q1', 'A');
insert into @theTable (StudentID, CourseName, TermCode, GradeEarned) values (2, 'Course 2', 'Q1', 'B');
insert into @theTable (StudentID, CourseName, TermCode, GradeEarned) values (2, 'Course 1', 'Q1', 'C');
insert into @theTable (StudentID, CourseName, TermCode, GradeEarned) values (3, 'Course 2', 'Q1', 'D');
insert into @theTable (StudentID, CourseName, TermCode, GradeEarned) values (5, 'Course 1', 'Q1', 'A');
insert into @theTable (StudentID, CourseName, TermCode, GradeEarned) values (6, 'Course 2', 'Q1', 'B');
insert into @theTable (StudentID, CourseName, TermCode, GradeEarned) values (7, 'Course 1', 'Q1', 'C');
insert into @theTable (StudentID, CourseName, TermCode, GradeEarned) values (8, 'Course 2', 'Q1', 'D');

--Pivot table
select StudentID, CourseName
	 , [Q1], [Q2], [Q3], [Q4]
  from (select * from @theTable) t1
 pivot (MAX(GradeEarned) FOR TermCode in ([Q1], [Q2], [Q3], [Q4])) as pt1
 

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LVL 49

Accepted Solution

by:
PortletPaul earned 1000 total points
ID: 39271147
Oracle Syntax (11g) for use of the pivot feature, if it is preferred:
SELECT *
FROM   (SELECT STUDENTID,COURSENAME, TERMCODE, GRADEEARNED
        FROM   YOURTABLE)
PIVOT  (MAX(GRADEEARNED) AS GRADE FOR (TERMCODE)  IN ('Q1' AS Q1, 'Q2' AS Q2, 'Q3' AS Q3, 'Q4' AS q4));

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