Help me plz urgent

Question

dear members
i have 2 tables
employee
empno number,
name varchar2(30),
deptno number);
attandance
empno number,
deptno number,
type varchar2(10)
i have 95000 record attandance table...now that time i have update employee table and update employee deptno...bcoze lot of employee chane his dept
so i want to create a query who update a attandance table deptno campare to employee table deptno..
any body help me
thanks a lot

Answer 1

Assuming that empno in attendance is a foreign key into employee, you really should only be storing deptno once. Storing redundant data in multiple tables is a sure-fire recipie for this sort of data integrit problem
UPDATE employee emp
   SET deptno = (SELECT deptno
                   FROM attendance att
                  WHERE emp.empno = att.empno)If there are employees in the emp table that don't exist in the attendance table, you would need to add a WHERE EXISTS clause to this to avoid setting the department number to NULL. If there are multiple rows in the attendance table for the same empno, you would have to modify the subquery to find a single row per employee number.
Justin
Distributed Database Consulting, Inc.
http://www.ddbcinc.com/askDDBC