efficient update program

Hi Friends,

I have a table emp with columns (hiredate date, birthdate date);
I want to update the two columns set to NULL if their value is
greater than sysdate. Like this:

sql> update emp set hiredate=null where hiredate>sysdate;
sql> update emp set birthdate=null where birthdate>sysdate;

How can i write this on one command line (maybe using decode)
so i wont re-read the table again, thus making it efficient.
I want one pass to the table.

Thanks a lot

Code:

---


update emp
  set hiredate =
                  case when hiredate > sysdate then
                      null
                  else hiredate end,
      birthdate =
                  case when birthdate > sysdate then
                      null
                  else birthdate end
where
  birthdate > sysdate or hiredate > sysdate

---

Abhay.

Thanks hun, hmmnnn new look in sqlplus command. it looks like
pl/sql...i learned a new technique again, if u want to evaluate/validate all columns you can use CASE.