Query to sort data by date of birth

Question

Hi i tried creating this query from the staff table of my database to display the data for only the nurses who are over 50 years old if the date of birth is shown.
my coding is below and so is the eroor that keeps occurring when i try to run it. please help if you can.
MY CODING:
SELECT Staff_Table.StaffNumber, Staff_Table.LastName, Staff_Table.FirstName, Staff_Table.JobDescription, Staff_Table.DateOfBirth
FROM Staff_Table
WHERE (((Staff_Table.JobDescription)="nurse") AND ((Staff_Table.DateOfBirth)<=DateAdd("yyyy",-50,Date())));
ERROR:
Error starting at line 1 in command:
SELECT Staff_Table.StaffNumber, Staff_Table.LastName, Staff_Table.FirstName, Staff_Table.JobDescription, Staff_Table.DateOfBirth
FROM Staff_Table
WHERE (((Staff_Table.JobDescription)="nurse") AND ((Staff_Table.DateOfBirth)<=DateAdd("yyyy",-50,Date())))
Error at Command Line:3 Column:36
Error report:
SQL Error: ORA-00920: invalid relational operator
00920. 00000 - "invalid relational operator"
*Cause:   
*Action:
I really dont understand what is wrong with this.

Answer 1

If you want to search on first name
SELECT  Staff_Table.StaffNumber,
        Staff_Table.LastName,
        Staff_Table.FirstName,
        Staff_Table.JobDescription,
        Staff_Table.DateOfBirth
  FROM  Staff_Table
  WHERE LOWER(Staff_Table.FirstName) = LOWER( <<entered first name>> )
    AND Staff_Table.DateOfBirth <= ADD_MONTHS(TRUNC(SYSDATE),-600)If you want to search on the last name
SELECT  Staff_Table.StaffNumber,
        Staff_Table.LastName,
        Staff_Table.FirstName,
        Staff_Table.JobDescription,
        Staff_Table.DateOfBirth
  FROM  Staff_Table
  WHERE LOWER(Staff_Table.LastName) = LOWER( <<entered last name>> )
    AND Staff_Table.DateOfBirth <= ADD_MONTHS(TRUNC(SYSDATE),-600)Or if you want to search on either
SELECT  Staff_Table.StaffNumber,
        Staff_Table.LastName,
        Staff_Table.FirstName,
        Staff_Table.JobDescription,
        Staff_Table.DateOfBirth
  FROM  Staff_Table
  WHERE (LOWER(Staff_Table.FirstName) = LOWER( <<entered name>> ) OR
        LOWER(Staff_Table.LastName) = LOWER( <<entered name>> ) )
    AND Staff_Table.DateOfBirth <= ADD_MONTHS(TRUNC(SYSDATE),-600)You could also put wild card character to search for the entered string anywhere in the first or last name field
SELECT  Staff_Table.StaffNumber,
        Staff_Table.LastName,
        Staff_Table.FirstName,
        Staff_Table.JobDescription,
        Staff_Table.DateOfBirth
  FROM  Staff_Table
  WHERE (LOWER(Staff_Table.FirstName) LIKE LOWER( '%' || <<entered name>> || '%' ) OR
        LOWER(Staff_Table.LastName) LIKE LOWER( '%' || <<entered name>> || '%'  ) )
    AND Staff_Table.DateOfBirth <= ADD_MONTHS(TRUNC(SYSDATE),-600)Of course, this gets harder and harder to build indexes that would allow you to find the rows without resorting to a full table scan.
Justin