Using outter joins

Question

need to create a report based on three tables: emp,dept, and loc. There dept can have null dept and loc and the user wants to see these records; therefore, we need to do an outter join. Also, the user wants to have bind variables so he/she can put any of these variables (dept or loc) and based on that return the records.
select emp.name, dept.name, loc.name
from emp, dept, loc
where dept.deptno = emp.deptno(+)
and loc.locid = emp.loc(+)
and dept.deptno = :department
and loc.locid = :location
I need to find and join those records that are null. I took the following approach, but I'm not sure if this is correct:
1. created a table based on emp and converted those null dept and loc w/ -1
2. joined the tables
3. do the query based on the table
4. the bind variable will have a like so that if the user doesn't insert a field I will have the wild card (%) so it will bring all records
select emp.name, dept.name, loc.name
from emp, dept, loc, (select nvl(deptno, -1) as deptno, nvl(loc, -1) as loc from emp) temp
where dept.deptno = emp.deptno(+)
and loc.locid = emp.loc(+)
and temp.deptno = nvl(dept.deptno, -1)
and temp.loc = nvl(loc.id, -1)
and temp.deptno like nvl(:department, '%')
and temp.locid like nvl(:location, '%')
I think that I'm overdoing this query though. Let me know!
;-P
Marcelo

Answer 1

Hi, since oracle 9i it is possible to use the ansi join syntax in Oracle sql.
You can use a "full out join", "left outer join", "right outer join"
Example return all rows with NULLs from all tables:
select e.last_name, d.department_name, d.department_id, j.job_title, l.city
from employees e
     full outer join departments d on (e.department_id=d.department_id )
     full outer join jobs j on (e.job_id=j.job_id)
     full outer join locations l on (l.location_id=d.location_id)
see docu: http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96540/statements_103a.htm#2107297
Lutz