--说明:复制表(只复制结构,源表名:a 新表名:b)
select * into b from a where 1<>1
--说明:拷贝表(拷贝数据,源表名:a 目标表名:b)
insert into b(a, b, c) select d,e,f from b;
--说明:显示文章、提交人和最后回复时间
select a.title
,a.username
,b.adddate
from table a
,(select max(adddate) adddate from table where table.title=a.title) b
--说明:外连接查询(表名1:a 表名2:b)
select a.a, a.b, a.c, b.c, b.d, b.f
from a
LEFT OUT JOIN b
ON a.a = b.c
--说明:日程安排提前五分钟提醒
select * from 日程安排 where datediff('minute',f开始时间,getdate())>5
--说明:两张关联表,删除主表中已经在副表中没有的信息
delete from info where not exists ( select * from infobz where info.infid=infobz.infid )