SQL & PL/SQL

Hi all,

Can someone tell me how oracle does minus operation? Is it a DML operation?

In data warehouse system, we are usually confronted with this kind of situations. To delete a great number rows from a much bigger data set.

For example, 10million rows should be removed from 10 Billion.

Let assume we can know or enumerate the rows that we should remove. I mean I can create the table
create table rows_to_delete nologging
as select /*+ parallel */ * from t where <filter condtions>;

Which is faster or more reasonable or more feasible of the following two method:

1. create table rows_to_keep nologging
as
(select * from t minus select * from rows_to_delete)

2. delete DML directly.

Or you may give a better solution?

Thank you very much.
Leon

Edited by: user12064076 on Dec 10, 2010 12:07 AM

Edited by: user12064076 on Dec 10, 2010 12:08 AM