Get averages from a cursor

Question

I Have something like this...
CURSOR my_cursor IS
SELECT avg(a),avg(b), avg(c), avg(d)
FROM sch.mytable;
How would i fetch this into a ROWTYPE variable? I keep getting null back.

Answer 1

Try this in TOAD or SQL*Plus
(I use a 9.2 version of Oracle)
--STEP 1: CREATE A TEST TABLE
CREATE TABLE MYTAB
(id NUMBER(4),
a NUMBER(10),
b NUMBER(10),
c NUMBER(10),
d NUMBER(10));
--STEP 2:  CREATE 10 RANDOM VALUES FOR YOUR TABLE
BEGIN
FOR idx IN 1..10 LOOP
INSERT INTO MYTAB(ID,a,b,c,d)
VALUES(idx,                          --ID value
          DBMS_RANDOM.VALUE(1,100), --random number between 1 to 100 for column a
     DBMS_RANDOM.VALUE(1,100), --random number between 1 to 100 for column a
     DBMS_RANDOM.VALUE(1,100), --random number between 1 to 100 for column a
     DBMS_RANDOM.VALUE(1,100)); --random number between 1 to 100 for column a
END LOOP
          COMMIT;
END;     
--STEP 3: VIEW RESULTS
SELECT * FROM MYTAB;
--***************   STEP 4: TEST YOUR CURSOR  ******/  
DECLARE
     CURSOR my_cursor IS
     SELECT AVG(a) AS avg_a,
          AVG(b) AS avg_b,
          AVG(c) AS avg_c,
          AVG(d) AS avg_d
     FROM MYTAB;
--Declare cursor pointer rowtype
c_my_cursor_rec my_cursor%ROWTYPE;
BEGIN
OPEN my_cursor;
LOOP
FETCH my_cursor INTO c_my_cursor_rec;
EXIT WHEN my_cursor%NOTFOUND;
DBMS_OUTPUT.PUT_LINE('Average(a) = '||c_my_cursor_rec.avg_a);
          DBMS_OUTPUT.PUT_LINE('Average(a) = '||c_my_cursor_rec.avg_b);
          DBMS_OUTPUT.PUT_LINE('Average(a) = '||c_my_cursor_rec.avg_c);
          DBMS_OUTPUT.PUT_LINE('Average(a) = '||c_my_cursor_rec.avg_d);
     END LOOP;
CLOSE my_cursor;
END;
--STEP 5: (Optional): 
-- CHANGE THE VALUES IN YOUR TABLE AND REPEAT STEPS ABOVE
BEGIN
FOR idx IN 1..10 LOOP
UPDATE MYTAB
     SET a = DBMS_RANDOM.VALUE(1,100), --random number between 1 to 100 for column a
     b = DBMS_RANDOM.VALUE(1,100), --random number between 1 to 100 for column a
     c = DBMS_RANDOM.VALUE(1,100), --random number between 1 to 100 for column a
     d = DBMS_RANDOM.VALUE(1,100); --random number between 1 to 100 for column a
END LOOP;
          COMMIT;
END;     
/