SELECT a.ID, AVG(a.grade) AVG_GRADE
FROM TableName a
INNER JOIN
(
SELECT ID, Subject, MAX(date) max_date
FROM TableName
WHERE ID = 1 -- <<== change it to p_id
GROUP BY ID, Subject
) b ON a.ID = b.ID AND
a.Subject = b.Subject AND
a.date = b.max_date
WHERE a.ID = 1 -- <<== change it to p_id
GROUP BY a.ID
sql: select average grade for all subjects for one student and print an according message
-
14-04-2022 - |
Question
I have a table student with the following columns:
id subject grade date
---|-------|------|-----------|
1 | A | 1 | 01-MAR-10 |
1 | A | 5 | 05-APR-10 |
1 | B | 3 | 01-JUN-10 |
2 | A | 1 | 01-MAR-10 |
2 | C | 3 | 01-APR-10 |
In my Procedure I pass the student id (p_id), and I need to select an average grade of all subjects for that student, if a student has 2 grades for the same subject, only the latest grade counts, like this:
for p_id=1:
id avgGrade
---|--------|
1 | 4 |
this is done by now
what I need to do now, to save the information about the student's success in a string and print it with DBMS_OUTPUT. the highest grade is 1, the lowest is 5. if a student had a single 5 (as a last grade for a subject), no matter what average he has, the string should contain "the student failed", if the student had no 5 as the last grade, and had an average of <= 1,5 , the string should contain "perfect average", otherwise just "the student passed"
the code so far is:
CREATE OR REPLACE Procedure avg_grade
( p_id IN number )
IS
cursor c1 is
select a.id, avg(a.grade) avg_grade
from student a
inner join
(
select id, subject, max(date) max_date
from student
where id=p_id
group by id, subject
)b ON a.id=b.id and
a.subject=b.subject and
a.date=b.max_date
where a.id=p_id
group by id;
cursor c2 is
select grade
from student
where id=p_id;
DECLARE @out as varchar(50)
SET @out=NULL
IF c2.grade IN(5)
BEGIN
SET @out='student failed'
END
ELSE IF c2.grade NOT IN(5) AND c1.avg_grade IN (BETWEEN 1 AND 1,5)
BEGIN
SET @out='student has a perfect average'
END
ELSE
BEGIN
SET @out='student passed'
END
DBMS_OUTPUT.PUT_LINE(@out);
please help
Solution