Thanks , for your inetrest , indeed....
The actual code is as follows...

CREATE OR REPLACE FUNCTION FNC_2WCOLUMN_1AGGRCOLUMN(TABLE_NAME_VAR IN VARCHAR2,COLUMN_NAME_VAR IN VARCHAR2,
AGGREGATION_TYPE_VAR IN VARCHAR2,AGGR_COLUMN_VAR IN VARCHAR2)
RETURN NUMBER

AS
CURRENT_EXET_NUMBER NUMBER;
SQL_STMT VARCHAR2(500);

BEGIN
CURRENT_EXET_NUMBER:=0;

BEGIN
SQL_STMT:='SELECT '||AGGREGATION_TYPE_VAR||'('||COLUMN_NAME_VAR||'),'||AGGR_COLUMN_VAR||' FROM '||TABLE_NAME_VAR||
' WHERE '||COLUMN_NAME_VAR||'=10 GROUP BY '||AGGR_COLUMN_VAR;
EXECUTE IMMEDIATE SQL_STMT INTO CURRENT_EXET_NUMBER;

END;
RETURN CURRENT_EXET_NUMBER;
END;

When I call the above function from SQL , I get ...

SQL> select FNC_2WCOLUMN_1AGGRCOLUMN('EMP','ENAME','COUNT','DEPTNO') FROM EMP;
-------
select FNC_2WCOLUMN_1AGGRCOLUMN('EMP','ENAME','COUNT','DEPTNO') FROM EMP

ORA-00932:

I have also tried the anonymous block - proposed by DAPI- with the same results....

Simon