Copying and updating Data from a table to new table using Merge command

Question

Hi ,
Can anyone please tell me how to do this?
I have a table : EMP(empno(pk),ename,sal,dept) another table is EMP_CLASS(empno(pk),ename)
I want to insert corresponding rows from emp to emp_class table if that row does'nt exist in emp_class
otherwise it will update corrsponding info in emp_class table as well as delete from emp_class according to emp delete operation.
Thanks ,
Deekay.
Edited by: Deekay on Aug 12, 2010 10:59 PM

Answer 1

Hi Vishu,
This is really helpful, but I want little modification like it will check for deptno in emp and insert in class field if dept is 10 then 1 ,20 ,2 like wise. I have changed emp_class structure .Please find my updated code eaccording to that ,but I am getting error.
MERGE
INTO emp_class
USING emp
ON  (emp.empno = emp_class.empno)
WHEN MATCHED
THEN
UPDATE
SET emp_class.ename = emp.calss_name,
    emp_class.deptno = emp.deptno,
    emp_class.class=select decode(deptno,10,1,20,2,30,3,40,4)from emp
DELETE
WHERE emp_class.empno = emp.empno
WHEN NOT MATCHED
THEN
INSERT (emp_class.empno,emp_class.name,emp_class.deptno,emp_class.class)
VALUES (emp.empno,emp.name,emp.sal,emp.deptno,decode(deptno,10,1,20,2,30,3,40,4)emp.class);
    Please help me to fix this.
this is the error:
MERGE
INTO emp_class
USING emp
ON (emp.empno = emp_class.empno)
WHEN MATCHED
THEN
UPDATE
SET emp_class.ename = emp.calss_name,
emp_class.deptno = emp.deptno,
emp_class.class=select decode(deptno,10,1,20,2,30,3,40,4)from emp
DELETE
WHERE emp_class.empno = emp.empno
WHEN NOT MATCHED
THEN
INSERT (emp_class.empno,emp_class.name,emp_class.deptno,emp_class.class)
VALUES (emp.empno,emp.name,emp.sal,emp.deptno,decode(deptno,10,1,20,2,30,3,40,4)emp.class);