Procedure takes several hours to complete - sql

Question

I'm trying to generate a report that give me the percentage of each grade for each letter for each term for each subject. The final report has subject codes like MAT, ENC, etc. as the row headers and then the terms and letter grades as the column headers. I'm currently looping through each subject, then each term, then each grade and it takes 2+ hours to complete. What is the correct/more efficient way of accomplishing this. Feel free to ask if you have any questions. Thanks for your help!!
v_subj varchar2(5);
v_grade varchar2(5);
v_termloop varchar2(6);
c_total number;
c_dfw number;
c_gradetotal number;
c_gradedfw number;
v_output varchar2(1000);
Cursor Get_Terms is
select distinct ssbsect_term_code from ssbsect
where ssbsect_term_code >= 201230
and ssbsect_term_code not like '%5'
order by 1;
Cursor Get_Subj is
Select distinct ssbsect_subj_code from ssbsect
where ssbsect_term_code >= 201230
and ssbsect_insm_code = 'DL'
and ssbsect_term_code not like '%5'
order by 1;
Cursor Get_Grade is
select distinct msvcrse_grde_code from msvcrse
where msvcrse_grde_code in ('A','B','C','D','F','S','U','W')
order by 1;
Cursor Get_Total is
select count(msvcrse_pidm) from msvcrse
join ssbsect on msvcrse_crn = ssbsect_crn
and msvcrse_Term_code = ssbsect_term_code
where msvcrse_term_code = v_termloop
and ssbsect_insm_code = 'DL'
and msvcrse_crse_numb < '3000'
and msvcrse_subj_code = v_subj
and msvcrse_gmod_code <> 'D';
Cursor Get_GradeTotal is
select count(msvcrse_pidm) from msvcrse
join ssbsect on msvcrse_crn = ssbsect_crn
and msvcrse_Term_code = ssbsect_term_code
where msvcrse_term_code = v_termloop
and ssbsect_insm_code = 'DL'
and msvcrse_grde_code like '%'||v_grade||'%'
and msvcrse_crse_numb < '3000'
and msvcrse_subj_code = v_subj
and msvcrse_gmod_code <> 'D';
Begin
Open Get_Subj;
Loop
Fetch Get_Subj into v_subj;
Exit when Get_Subj%NOTFOUND;
v_output := '';
v_output := v_subj;
Open Get_Terms;
Loop
Fetch Get_Terms into v_termloop;
Exit when Get_Terms%NOTFOUND;
Open Get_Grade;
Loop
Fetch Get_Grade into v_grade;
Exit when Get_grade%NOTFOUND;
Open Get_Total;
Fetch Get_Total into c_total;
Close Get_Total;
Open Get_GradeTotal;
Fetch Get_GradeTotal into c_gradetotal;
Close Get_GradeTotal;
if c_total = 0 then
c_total := NULL;
end if;
v_output := v_output ||'|'||nvl(100*(round(c_gradetotal/c_total,3)),0);
--dbms_output.put_line(v_subj||'|'||v_termloop||'|'||v_insm||'|'||nvl(100*(round(c_dfw/c_total,3)),0));
End Loop;
Close Get_Grade;
End Loop;
Close Get_Terms;
dbms_output.put_line(v_output);

Answer 1

I change a little bit your code, but the result should be the same.
Please merge the cursors get_grade and get_gradetotal, makes no sense have two in this code.
DECLARE
c_total NUMBER;
v_output VARCHAR2 ( 1000 );
CURSOR get_subj IS
SELECT DISTINCT ssbsect_subj_code
FROM ssbsect
WHERE ssbsect_term_code >= 201230
AND ssbsect_insm_code = 'DL'
AND ssbsect_term_code NOT LIKE '%5'
ORDER BY 1;
CURSOR get_terms IS
SELECT DISTINCT ssbsect_term_code
FROM ssbsect
WHERE ssbsect_term_code >= 201230
AND ssbsect_term_code NOT LIKE '%5'
ORDER BY 1;
CURSOR get_total ( lci_termloop IN ssbsect.msvcrse_term_code%TYPE
, lci_subj IN msvcrse.msvcrse_subj_code%TYPE ) IS
SELECT COUNT ( msvcrse_pidm )
FROM msvcrse
JOIN ssbsect
ON msvcrse_crn = ssbsect_crn
AND msvcrse_term_code = ssbsect_term_code
WHERE msvcrse_term_code = lci_termloop
AND ssbsect_insm_code = 'DL'
AND msvcrse_crse_numb < '3000'
AND msvcrse_subj_code = lci_subj
AND msvcrse_gmod_code <> 'D';
CURSOR get_grade IS
SELECT DISTINCT msvcrse_grde_code
FROM msvcrse
WHERE msvcrse_grde_code IN ('A', 'B', 'C', 'D', 'F', 'S', 'U', 'W')
ORDER BY 1;
CURSOR get_gradetotal ( lci_termloop IN ssbsect.msvcrse_term_code%TYPE
, lci_grade IN msvcrse.msvcrse_grde_code%TYPE
, lci_subj IN msvcrse.msvcrse_subj_code%TYPE ) IS
SELECT COUNT ( msvcrse_pidm ) AS msvcrse_pidm
FROM msvcrse
JOIN ssbsect
ON msvcrse_crn = ssbsect_crn
AND msvcrse_term_code = ssbsect_term_code
WHERE msvcrse_term_code = lci_termloop
AND ssbsect_insm_code = 'DL'
AND msvcrse_grde_code LIKE '%' || lci_grade || '%'
AND msvcrse_crse_numb < '3000'
AND msvcrse_subj_code = lci_subj
AND msvcrse_gmod_code <> 'D';
BEGIN
FOR rec_subj IN get_subj LOOP
v_output := rec_subj.ssbsect_subj_code;
FOR rec_term IN get_terms LOOP
OPEN get_total ( lci_termloop => rec_term.ssbsect_term_code
, lci_subj => rec_subj.ssbsect_subj_code );
FETCH get_total INTO c_total;
CLOSE get_total;
FOR rec_grade IN get_grade LOOP
<<grade_total>>
FOR rec_gradetotal IN get_gradetotal ( lci_termloop => rec_term.ssbsect_term_code
, lci_grade => rec_grade.msvcrse_grde_code
, lci_subj => v_output ) LOOP
IF c_total = 0 THEN
c_total := NULL;
v_output := v_output || '|';
CONTINUE grade_total; -- <-- AVOID WORK
END IF;
v_output := v_output || '|' || NVL ( 100 * ( ROUND ( rec_gradetotal.msvcrse_pidm / c_total, 3 ) ), 0 ); -- <-- PLEASE MAKE THIS CODE BETTER
--dbms_output.put_line(rec_subj.ssbsect_subj_code||'|'||rec_term.ssbsect_term_code||'|'||v_insm||'|'||nvl(100*(round(c_dfw/c_total,3)),0));
END LOOP grade_total;
END LOOP;
END LOOP;
--DBMS_OUTPUT.put_line ( rec_subj.ssbsect_subj_code );
END LOOP;
END;
I change all code without compile, please make sure the types used int the cursor.
I guess 50% of improvement, but you need test.
Let me know whether you have any question and please use table alias in SQL and be careful with loops.
Thank you.