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oracle常用经典SQL查询

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  25. 查询表空间的碎片程度

  select tablespace_name,count(tablespace_name) from dba_free_space group by tablespace_name

  having count(tablespace_name)>10;

  alter tablespace name coalesce;

  alter table name deallocate unused;

  create or replace view ts_blocks_v as

  select tablespace_name,block_id,bytes,blocks,'free space' segment_name from dba_free_space

  union all

  select tablespace_name,block_id,bytes,blocks,segment_name from dba_extents;

  select * from ts_blocks_v;

  select tablespace_name,sum(bytes),max(bytes),count(block_id) from dba_free_space

  group by tablespace_name;

  26。查询有哪些数据库实例在运行

  select inst_name from v$active_instances;

  ===========================================================

  ######### 创建数据库----look $ORACLE_HOME/rdbms/admin/buildall.sql #############

  create database db01

  maxlogfiles 10

  maxdatafiles 1024

  maxinstances 2

  logfile

  GROUP 1 ('/u01/oradata/db01/log_01_db01.rdo') SIZE 15M,

  GROUP 2 ('/u01/oradata/db01/log_02_db01.rdo') SIZE 15M,

  GROUP 3 ('/u01/oradata/db01/log_03_db01.rdo') SIZE 15M,

  datafile 'u01/oradata/db01/system_01_db01.dbf') SIZE 100M,

  undo tablespace UNDO

  datafile '/u01/oradata/db01/undo_01_db01.dbf' SIZE 40M

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