常用sql语句

1.限制返回记录的行数（4-10行）
select rownum,c1 from t144 where rownum<10
minus
select rownum,c1 from t144 where rownum<5
2.批量插入
insert into tablename(select * from othertable)
或
insert into (column1,column2,,,,,,,)tablename(select column1,column2,,,,,,,from othertable)
3,分组函数(结果中出现的列要在group by 中出现)
select count(age), username, , ,... from table   group by age,usename,,,,...
4.查看数据库中的存在的表
select table_name  from dba_tables (include all users)
select * from tab(include view)
5.高效update，一次修改多个列
update smsmonitor sms
 set (sms.smsmonitor_sendflag, sms.smsmonitor_maxnum) = (select s.smsmonitor_sendflag,
                                                                  s.smsmonitor_maxnum
                                                             from smsmonitor s
                                                            where s.smsmonitor_id =
                      &nbs