--mysql

alter table user modify name  varchar2 (32);

--oracle

alter table A modify(name varchar2(4000))

mysql>ALTER TABLE `table_name` ADD PRIMARY KEY ( `column` )

mysql>ALTER TABLE `table_name` ADD UNIQUE (`column`)

mysql>ALTER TABLE `table_name` ADD INDEX index_name ( `column` )

mysql>ALTER TABLE `table_name` ADD FULLTEXT ( `column`)

mysql>ALTER TABLE `table_name` ADD INDEX index_name ( `column1`, `column2`, `column3` )

select * from ok.table_001_reg t where to_char(order_id) in (select to_char(t.order_id) from ok.table_002 t where  t.test_sn ='7777601') for update;

delete  from ok.table_001_reg t where to_char(order_id) in (select to_char(t.order_id) from ok.table_002 t where  t.test_sn  in ('7777601'));

select b.owner,b.object_name,a.session_id,a.locked_mode

from v$locked_object a,dba_objects b

where b.object_id = a.object_id;

select b.username,b.sid,b.serial#,logon_time

from v$locked_object a,v$session b

where a.session_id = b.sid order by b.logon_time;

ALTER system kill session '789, 7296';

CREATE TABLESPACE TBS_TR_DATA

DATAFILE '/oradata/rTBS_TR_DATA_001.dbf'

SIZE 64G

EXTENT MANAGEMENT LOCAL

SEGMENT SPACE MANAGEMENT AUTO ONLINE;

select tablespace_name,status from dba_tablespaces;

SELECT tablespace_name,file_id,file_name,round(bytes / (1024 * 1024), 0) total_space FROM dba_data_files ORDER BY tablespace_name;

SELECT a.tablespace_name,

a.bytes/(1024*1024) total_M,

b.bytes/(1024*1024) used_M,

c.bytes/(1024*1024) free_M,

(b.bytes * 100) / a.bytes "% USED ",

(c.bytes * 100) / a.bytes "% FREE "

FROM sys.sm$ts_avail a, sys.sm$ts_used b, sys.sm$ts_free c

WHERE a.tablespace_name = b.tablespace_name

AND a.tablespace_name = c.tablespace_name;

select a.name, b.*

from v$tablespace a,

(select tablespace_id,

trunc(to_date(rtime, 'mm/dd/yyyy hh24:mi:ss')) datetime,

max(tablespace_usedsize * 8 / 1024) used_size

from dba_hist_tbspc_space_usage

where trunc(to_date(rtime, 'mm/dd/yyyy hh24:mi:ss')) >

trunc(sysdate - 30) group by tablespace_id,

trunc(to_date(rtime, 'mm/dd/yyyy hh24:mi:ss')) order by

tablespace_id, trunc(to_date(rtime, 'mm/dd/yyyy hh24:mi:ss'))) b

where a.ts# = b.tablespace_id ;

-- 修改建立的数据文件的大小

SQL> col file_name for a60

SQL> select file_name,bytes/1024/1024 from dba_data_files;

SQL> alter database datafile '/home/oracle/app/oradata/orcl/users01.dbf'resize 51M;

SQL> select file_name,bytes/1024/1024 from dba_data_files;

-- 增加表空间的数据文件

SQL> alter tablespace andy add datafile '/home/oracle/app/oradata/orcl/andy02.dbf'size 1M

autoextend on next 1m maxsize 2m ;

drop tablespace XXX including contents and contents;

alter tablespace tablespace_name rename to new_table_name;

alter tablespace andy rename to newandy;

SQL> select tablespace_name,file_name from dba_data_files where tablespace_name = 'NEWANDY';

SQL> alter tablespace newandy offline;

[oracle@11g ~]$ mv /home/oracle/app/oradata/orcl/andy01.dbf /home/oracle/app/oradata/andy01.dbf

SQL> alter tablespace newandy rename datafile '/home/oracle/app/oradata/orcl/andy01.dbf' to '/home/oracle/app/oradata/andy01.dbf';

SQL> alter tablespace newandy online;

SQL> select tablespace_name,file_name from dba_data_files where tablespace_name = 'NEWANDY';

SQL> select tablespace_name,status,extent_management,SEGMENT_SPACE_MANAGEMENT from dba_tablespaces;

SQL> alter database datafile file_name autoextend off|on [next number K|M maxsize unlimited|number K|M]

SQL> select tablespace_name,status,extent_management,SEGMENT_SPACE_MANAGEMENT from dba_tablespaces;

--从任意ip地址连接的用户名为root，密码为123的用户赋予所有的权限。其中的"%"为任意的ip地址，如果想设为特定的值也可以设定为特定的值。 执行了该语句后就可以在其他机器上以root:123访问到该机器上了

grant all privileges on   *.* to root@"%" identified by '123' with grant option;   flush privileges;   

--给来自10.163.225.87的用户joe分配可对数据库vtdc的employee表进行select,insert,update,delete,create,drop等操作的权限，并设定口令为123。

mysql>grant select,insert,update,delete,create,drop on vtdc.employee to joe@10.163.225.87 identified by ‘123′;

--给来自10.163.225.87的用户joe分配可对数据库vtdc的employee表进行select,insert,update,delete,create,drop等操作的权限，并设定口令为123。

mysql>grant select,insert,update,delete,create,drop on vtdc.employee to joe@10.163.225.87 identified by ‘123′;

--给来自10.163.225.87的用户joe分配可对数据库vtdc所有表进行所有操作的权限，并设定口令为123。

mysql>grant all privileges on vtdc.* to joe@10.163.225.87 identified by ‘123′;

--给来自10.163.225.87的用户joe分配可对所有数据库的所有表进行所有操作的权限，并设定口令为123。

mysql>grant all privileges on *.* to joe@10.163.225.87 identified by ‘123′;

--给本机用户joe分配可对所有数据库的所有表进行所有操作的权限，并设定口令为123。

mysql>grant all privileges on *.* to joe@localhost identified by ‘123′;

--将两个用户对两个表的所有操作权限收回

REVOKE ALL PRIVILEGES ON TABLE A,B,C FROM U1,U2;

--将所有用户对表A的所有查询权限收回

REVOKE SELECT ON TABLE A FROM PUBLIC;

--将用户U1对表A的Tname的修改权限收回

REVOKE UPDATE(Tname) ON TABLE A FROM U1;

--单独密码修改(mysql)

alter user 'root'@'localhost' identified by '123456'修改root本地密码为123456