oracle 常用语句

-- 查询锁表
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;
-- 杀死锁表进程
select 'alter system kill session '''||b.sid||','||b.serial#||''';' from v$locked_object a,v$session b where a.session_id = b.sid order by b.logon_time;

-- 查看数据文件和表空间对应的大小
-- 数据文件最大32767M
select file_id,file_name,tablespace_name,status,bytes/1024/1024 as "bytes MB" from dba_data_files
-- 为表空间增加数据文件，并开启自动增长
ALTER  TABLESPACE user ADD DATAFILE 'D:APPRONGHIORADATAORCLUSERS02.DBF' SIZE 1G AUTOEXTEND ON NEXT 5M MAXSIZE UNLIMITED;
-- 设置数据文件自动增长
-- alter database datafile '/oracle/oraoms/user.dbf'  autoextend on;

-- 关联更新数据 https://www.cnblogs.com/relucent/p/4166544.html
MERGE INTO  TEST T1
USING (SELECT '2' as ID, 'newtest2' as NAME FROM dual) T2 on (T1.ID=T2.ID)
WHEN MATCHED THEN UPDATE SET T1.NAME=T2.NAME
WHEN NOT MATCHED THEN  INSERT (T1.ID, T1.NAME) VALUES (T2.ID, T2.NAME ); 

-- 空表处理
select 'alter table '||table_name||' allocate extent;' from user_tables where num_rows=0

-- 拼接列
select listagg(sysdate,',')within group(order by 1)name from dual

-- listagg相反
SELECT id,
         rtrim(regexp_substr(str || ',', '.*?' || ',', 1, LEVEL), ',') AS str
    FROM str_table
  CONNECT BY id = PRIOR id
         AND PRIOR DBMS_RANDOM.VALUE IS NOT NULL
         AND LEVEL <= regexp_count(str || ',', ',')