select nvl(sum(t.dwxhl),1) from tb_jhde t where zydm=-1这里关心的nvl的用法,nvl(arg,value)代表如果前面的arg的值为null那么返回的值为后面的value
2、系统表
select object_name from user_objects where object_type='VIEW'; 查询所有的视图
select * from all_views;
SELECT distinct type FROM ALL_SOURCE;
select text from user_source;
selct text from dba_source;
SELECT * FROM ALL_TABLES;系统里有权限的表
SELECT * FROM DBA_TABLES; 系统表
SELECT * FROM USER_TABLES; 当前用户下的表
二、创建表空间
创建临时表空间
create temporary tablespace etllog_temp
tempfile 'D:/oracle/product/10.2.0/oradata/orcl/etllog_temp01.dbf'
size 32m
autoextend on
next 32m maxsize 2048m
extent management local;
创建数据表空间
create tablespace TSP_CPSR_GEODB_PROVINCE
logging
datafile 'F:''oracle''oradata''TSP_CPSR_GEODB_PROVINCE.dbf' size 1000M
extent management local segment
space management auto;
创建用户,分配权限
create user tyzcData identified by tyzcData
default tablespace etllog_data
temporary tablespace etllog_temp;
grant connect,resource,dba to tyzcData;
将密码有效期由默认的180天修改成“无限制”:
ALTER PROFILE DEFAULT LIMIT PASSWORD_LIFE_TIME UNLIMITED;
1 将数据库tyzc完全导出,用户名tyzc 密码tyzc 导出到D:tyzc01.dmp中
exp tyzcr/tyzc@orcl file=d:tyzc01.dmp full=y
2 1 将D:tyzc01.dmp 中数据导入 tyzc数据库中
imp tyzc/tyzc@orcl file=D:tyzc01.dmp
imp tyzc/tyzc@orcl full=y file=D:tyzc01.dmpignore=y