菜鸟到高手:SQL开发进阶常用精妙语句
说明:复制表(只复制结构,源表名:a 新表名:b)
sql: 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)
sql: 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
sql: 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)
sql: 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
sql: 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
sql:
delete from info
where not exists ( select * from infobz where info.infid=infobz.infid
说明:--
sql:
select a.num, a.name, b.upd_date, b.prev_upd_date
from table1,
(select x.num, x.upd_date, y.upd_date prev_upd_date
from (select num, upd_date, inbound_qty, stock_onhand
from table2
where to_char(upd_date,’yyyy/mm’) = to_char(sysdate, ’yyyy/mm’)) x,
(select num, upd_date, stock_onhand
from table2
where to_char(upd_date,’yyyy/mm’) =
to_char(to_date(to_char(sysdate, ’yyyy/mm’)




