摘要：
--A低效率 select t.* from ( select * from GET_ENTER_EXAM_SCORE t where signupyear='2013' and signupseason='春季') t where rownum <100--B高效率 select t.* from ( select b.*,rownum r from (select * from GET_ENTER_EXAM_SCORE a where signupyear='2013' and signupseason='春季' ord 阅读全文
摘要：
1）查看各表空间分配情况SQL> select tablespace_name, sum(bytes) / 1024 / 1024 from dba_data_files group by tablespace_name; TABLESPACE_NAME SUM(BYTES)/1024/1024------------------------------ --------------------UNDOTBS1 100SYSAUX ... 阅读全文