Question: I got this two columns

```
SQL> SELECT COUNT(A),CAR                                                        
  2  FROM ASIGNATURA                                                            
  3  GROUP BY CAR;                                                              

COUNT(A)        CAR

 1          1
 1          6
 1          2
 2          4
 1          5
 1          8
 4          7
 1          3

```

8 rows selected.

```
SQL> SELECT AVG(COUNT(A)),CAR                                                   
2  FROM ASIGNATURA                                                            
3  GROUP BY CAR;                                                              

SELECT AVG(COUNT(A)),CAR                     *
ERROR at line 1:
ORA-00937: not a single-group group function

```

I want the average of the two columns like:

```
 1/12   1
 1/12   6
 1/12   2
 2/12   4

 etc... 

```

How can I do it?

Answer: 
You are not actually calculating the average, but, display it to look like an average.

Try:

```
SELECT COUNT(CAR)
  ||'/'
  ||
  (SELECT COUNT(*) AS TOTAL FROM ASIGNATURA
  ) cnt_avg,
  CAR
FROM ASIGNATURA
GROUP BY CAR;

```

**Demo** using standard EMP table in SCOTT schema:

```
SQL> SELECT COUNT(deptno)
  2    ||'/'
  3    ||
  4    (SELECT COUNT(*) AS TOTAL FROM emp
  5    ) cnt_avg,
  6    deptno
  7  FROM emp
  8  GROUP BY deptno;

CNT_AV     DEPTNO
------ ----------
6/14           30
5/14           20
3/14           10

```
May be this will work

```
SELECT COUNT(A)/(SELECT COUNT(*) AS TOTAL FROM SIGNATURA B),CAR
FROM SUGNATURA
GROUP BY CAR

```