How to return employees who did not register?

Question

Hi All.
I've tow tables, employees (for data of employees) and emp_comm(emp_no number, comm_date date) for registering coming
emp_no in emp_comm table is a foreign key references to the primary one emp_no in employees.
Now I tried to use this code in a report to return all employees who didn't register between tow dates (using user parameters):
select a.FINANCIAL_NO ,  a.emp_full_name, b.xdate from
employees a,
(select to_date(:P_FROM,'dd/mm/yyyy') + (level-1) xdate  
from dual
connect by level <= to_date(:P_TO,'dd/mm/yyyy')-to_date(:P_FROM,'dd/mm/yyyy')+1
) b
where (A.EMP_NO, b.xdate) not in (select EMP_NO, TO_DATE(COMM_DATE, 'DD/MM/YYYY') from EMP_COMM)
But the previous code returns all the employees not only who not register! Why? and How to solve?
Thank you
Note: I'm using DB 10g, Reports 6i
Out Of Stock

Answer 1

Hello,
in your query
FROM    employees a
      ,(SELECT TO_DATE(:p_from,'dd/mm/yyyy') + (LEVEL - 1) xdate
        FROM    dual
        CONNECT BY LEVEL <= TO_DATE(:p_to,'dd/mm/yyyy') - TO_DATE(:p_from,'dd/mm/yyyy') + 1
        ) b
gives a cartesian product - every employee with every date
Since comm_date matches only a single date in b you get a NOT IN for every other date.
Try
SELECT  a.financial_no
      ,a.emp_full_name
FROM    employees a
WHERE  a.comm_date NOT BETWEEN TO_DATE(:p_from,'dd/mm/yyyy')
            AND TO_DATE(:p_to,'dd/mm/yyyy')
What do you need b.xdate for in your example?
BTW: Isn't comm_date a date column? TO_DATE on a date column is wrong, it might give you wrong results because it will implicitly converted to TO_DATE(TO_CHAR(comm_date),'dd/mm/yyyy') where the TO_CHAR uses the default date format.
Regards
Marcus