oracle常用SQL

一、简单查看oracle的连接情况和内存使用情况.

1、select machine,count(*) from v$session group by machine;

2、select machine,status,count(*) from v$session group by machine,status order by status;

二、Oracle 11g设置内存自动管理:

ALTER SYSTEM SET MEMORY_TARGET = 1024M SCOPE=SPFILE;

ALTER SYSTEM SET memory_max_target = 1500M SCOPE=SPFILE;

ALTER SYSTEM SET SGA_TARGET = 0 SCOPE=SPFILE;

ALTER SYSTEM SET SGA_MAX_SIZE=800M SCOPE=SPFILE;

ALTER SYSTEM SET PGA_AGGREGATE_TARGET = 0 SCOPE=SPFILE;

alter system set pre_page_sga=FALSE scope=spfile;

三、oracle查看允许的最大连接数和当前连接数等信息

1、当前的数据库连接数

select count(*) from v$process

2、数据库允许的最大连接数

select value from v$parameter where name = 'processes'

3、修改最大连接数:

alter system set processes = 300 scope = spfile;

4、查看当前有哪些用户正在使用数据

SELECT osuser, a.username,cpu_time/executions/1000000||'s', b.sql_text,machine

from v$session a, v$sqlarea b

where a.sql_address =b.address order by cpu_time/executions desc;

SELECT osuser, a.username,cpu_time/executions/1000000||'s', b.sql_text,machine

from v$session a, v$sqlarea b

where a.sql_address =b.address order by cpu_time/executions desc;

5、当前的session连接数

select count(*) from v$session

6、并发连接数

select count(*) from v$session where status='ACTIVE'

7、查看当前Oracle数据库名称

select name from v$database;

8、查看Oracle实例名称

select instance_name from v$instance;

9、查看Oracle域名

select value from v$parameter where name = 'db_domain';

10、查看Oracle服务名

select * from v$parameter where name = 'service_name';

11、游标实例

declare

v_tabname varchar2(30);

l_nc number;

l_sqltext varchar2(100);

begin

v_tabname:='t_affiche';

execute immediate 'select count(*) from ' || v_tabname

into l_nc;

dbms_output.put_line(l_nc);

end;

12、查询出列数据中仅包括数字的数据：

select * from 表 where not regexp_like(列名,'^[[:digit:]]+$');

加入条件

where length(translate(a,'-.0123456789'||a,'-.0123456789'))<>length(a)