sql性能优化
ORACLE学习笔记--性能优化(6) http://www.51cto.com 2005-08-11 00:00 <19>. /*+MERGE(TABLE)*/能够对视图的各个查询进行相应的合并.例如:SELECT /*+MERGE(V) */ A.EMP_NO,A.EMP_NAM,B....
分析函数
--取得所占的百分比select banji, fenzu, sum(chengji) chengji, ratio_to_report(sum(chengji)) o...
查询进程并杀掉
SELECT p.spid, a.serial#, c.object_name, b.session_id, b...
查询过去执行过的程序
select b.SQL_TEXT,b.FIRST_LOAD_TIME,b.SQL_FULLTEXT from v$sqlarea bwhere b.FIRST_LOAD_TIME between '2012-08-13/09:24:47' and '2012-08-14/09:24:47' order by b....
把多条记录合并成一条记录
SQL> SQL> create table IDTABLE2 (3 id number,4 val varchar2(20)5 )6 ;Table createdSQL> SQL> insert into IDTABLE (ID, VAL)2 values (10, 'abc');1 row insertedSQL> ...
新建类型
用 create type 变量 as table of 类型和 create type 变量 as object(字段1 类型1,字段2 类型2);与 type 变量 is table of 类型 和 type 变量 is record(字段1 类型1,字段2 类型2);区别是 用 create 后面用...
用下列SQL工具找出低效SQL
SELECT EXECUTIONS , DISK_READS, BUFFER_GETS, ROUND((BUFFER_GETS-DISK_READS)/BUFFER_GETS,2) Hit_radio, ROUND(DISK_READS/EXECUTIONS,2) Reads_per_run, SQL_TEXT FROM V$SQLAREA WHERE EXECUTIONS>0 AND BUFFE...
看谁在执行什么程序
SELECT osuser, username, sql_text from v$session a, v$sqltext b where a.sql_address = b.address &n...