Topic: In Oracle, What is DUAL? what info can I get from DUAL? @拉斯维加斯华人论坛:拉斯维加斯枫下论坛 The Rolia Forum of Las Vegas

工作学习 / IT技术讨论 / In Oracle, What is DUAL? what info can I get from DUAL? -xxu999(xxu999); 2001-11-12 (#258523@0)

whatis.com -wjiang(☆激昂☆); 2001-11-12 (#258531@0)
dual is a dummy table. you can get sysdate,or a sequence from dual.you can get anything that is not in a real table. for example:
select 2+1 from dual;
how ever,this statement is not useful. -laotang(laotang); 2001-11-12 {125} (#259314@0)

I think it could be useful when you are lazy and want SQL to do some calculation for you: "select some_date + 280 days from dual". Right? -abba(Spitfire); 2001-11-12 (#259319@0)

yes,it's true. u r smart. -laotang(laotang); 2001-11-12 (#259637@0)
select to_date('my departure day','yyyymmdd') + 182 from dual; 算什么时候必须再入境，就更有用了。 -yifan(yifan); 2001-11-13 (#259711@0)

It can be deleted. (delete from dual; note: dual belongs to sys) But why you delete it. -onewayticket(onewayticket); 2001-11-13 (#260115@0)

Just to do a test for fun. Is it posible for me to recover it? -cyt(会飞的鹿); 2001-11-13 (#260646@0)

For fun, you can try to insert another row into this table, hehe. -mickeymouse(㊣Oracle); 2001-11-13 (#260656@0)

egg will break if it contains more than one row, read this... -rootbear(喝点啤酒晕晕头); 2001-11-14 {954} (#260689@0)
hehe! Try it before you leave your office and be prepared to explain the failed night jobs to your manager next morning. -abba(Spitfire); 2001-11-14 (#260711@0)
Wow! It's so easy. I just inserted that record. Thanks, glad to know all you database guys here. Don't worry for me. I never do any test on the database other than the one only for me to play with. -cyt(会飞的鹿); 2001-11-14 (#261131@0)

@Las Vegas