RE: function help ???

From: Scott Crabtree <scott_at_psscorp.com>
Date: Mon, 03 Dec 2001 14:50:15 -0800
Message-ID: <F001.003D3EEA.20011203144104@fatcity.com>

Andrea,

Here is a version of the function you asked for, IT IS NOT WELL TESTED, should give you something to go on.

Scott Crabtree

FUNCTION calc_avg (student_id IN NUMBER)

RETURN NUMBER
AS

CURSOR student_c
IS

      SELECT      snum
               || call# class, credit, RTRIM (grade) grade,
                 credit
               * DECODE (RTRIM (grade), 'A', 4, 'B', 3, 'C', 2, 'D', 1, 'F',
0) weight
          FROM enrollment
         WHERE student# = student_id
      ORDER BY grade DESC;

   last_class    NUMBER              := 0;
   last_weight   NUMBER              := 0;
   last_credit   NUMBER              := 0;
   last_grade    VARCHAR2 (1)        := 'Z';
   cum_weight    NUMBER              := 0;
   cum_credits   NUMBER              := 0;
   gpa           NUMBER (5, 2)       := 0.00;

   student_rec student_c%ROWTYPE;
BEGIN
   OPEN student_c;
   FETCH student_c INTO student_rec;

WHILE student_c%FOUND
LOOP
--DBMS_OUTPUT.PUT_LINE(to_char(student_rec.weight) || ' ' ||
nvl(to_char(student_rec.credit),'NULL'));

      IF      last_class = student_rec.class  --Repeat_delete 
          AND last_grade IN ('F', 'D')
          AND student_rec.grade IN ('A', 'B', 'C')
      THEN
         cum_weight :=   cum_weight
                       - last_weight
                       + student_rec.weight;
         cum_credits :=   cum_credits
                        - last_credit
                        + student_rec.credit;


      --DBMS_OUTPUT.PUT_LINE(to_char(student_rec.weight) ||

to_char(student_rec.credit));
      ELSE
         cum_weight :=   cum_weight
                       + student_rec.weight;
         cum_credits :=   cum_credits
                        + student_rec.credit;
      END IF;

      last_class := student_rec.class;
      last_weight := student_rec.weight;
      last_credit := student_rec.credit;
      last_grade := student_rec.grade;
      FETCH student_c INTO student_rec;

END LOOP; CLOSE student_c;
gpa := cum_weight / cum_credits;

DBMS_OUTPUT.PUT_LINE('Cum Weight:' || to_char(cum_weight) || ' Cum Credits:' || to_char(cum_credits)); RETURN gpa; END; -- Function CALC_AVG

Call it for every distinct student# using:

select calc_avg(student),a.student from (select distinct STUDENT# student from enrollment) a

-----Original Message-----
Sent: Monday, December 03, 2001 12:12 PM To: Multiple recipients of list ORACLE-L

Hi, Could any one show me how to write the following function? Thank you very, very much!

The GPA Function

A GPA is calculated in the following fashion: Assume a student receives an A on a 3-credit_hour course and a D on a 2-credit-hour course. His grade is (4*3+1*2)/(3+2)=2.8.

2.Repeat_delete Policy: A student may repeat a course as many times as he
wants. However, if the first grade he receives on this course is a D or F,
then the second grade will automatically replaces the first grade, and the
first enrollment will not go into his GPA calculation. Under any other
circumstances, his grades will be considered as a regular grade and be
taken into consideration for GPA.

create table Enrollment(
Student# NUMBER (7),
SNUM NUMBER (5),
Call# NUMBER (7),
Semester char (8),
GRADE char (3),
Credit number,
Withdraw_Date Date);

SNUM + Call# represents one class.

Insert into Enrollment
values('58001','111','70070','Sp2000','F',3, null); Insert into Enrollment
values('58001','111','70070','Fa2000','B',3, null); Insert into Enrollment
values('58003','222','70070','Sp2000','A',2, null); Insert into Enrollment
values('58004','333','80025','Fa2000','A',2, null); Insert into Enrollment
values('58005','222','80025','Fa2000','C',3, null);

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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Andrea Oracle
  INET: andreaoracle_at_yahoo.com

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-- 
Author: Scott Crabtree
  INET: scott_at_psscorp.com

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San Diego, California        -- Public Internet access / Mailing Lists
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also send the HELP command for other information (like subscribing).

Received on Mon Dec 03 2001 - 16:50:15 CST