本人认为很实用的几条语句
1）select ... from ...into...
2）insert into ...select ...
3）select ...from ...left join ...on ...
4)case...when...then ...else ... end
Java代码
select * from directory_type
where (case when create_date is null then sysdate else create_date end ) >=‘08/04/2007‘
create table test1 as select * from user;-----将user里面的字段以及数据全部复制到test1这张表里面
原文：http://www.cnblogs.com/SZ2015/p/4719549.html