ITPub博客

group functionsum() avg() max() min()the group function will not handle null value except count(*).count(*)　return all rows including null;count(expr) return the not null rows.SQL> select count(*) ,count(comm) from emp; COUNT(*) COUNT(COMM)---------- ----------- 14 4count(distinct expr) select column,group_function(expr_column) from table group by column order by expr;--group by column having group_condition order by不使用别名或数字作为order by 的排序条件，因为有可能会导致优

昨天晚上无缘无故失眠了，今天又感冒了，所以就成悲剧了。该锻炼身体了，估计是体质变差的原因。想想也是，好久没有锻炼了，身上都开始长坠肉了，从今天开始锻炼。好了，不写了去锻炼了。[@more@]

BFILENAME BFILENAME returns a BFILE locator that is associated with a physical LOB binary file on the server file system.FILEISOPEN FunctionThis function finds out whether a BFILE was opened with the given FILE locator.SyntaxDBMS_LOB.FILEISOPEN ( file_loc IN BFILE) RETURN INTEGER; LOADFROMFILE Procedure This procedure copies all, or a part of, a source external LOB (BFILE) to a destination internal LOB. Syntax DBMS_LOB.LOADFROMFILE ( dest_lob IN OUT NOCOPY BLOB, src_

[oracle@RAC1 ~]$ crs_stat -tName Type Target State Host------------------------------------------------------------ora....11.inst application ONLINE ONLINE rac1ora....12.inst application ONLINE OFFLINEora.RACDB1.db application ONLINE ONLINE rac1ora....SM1.asm application ONLINE ONLINE rac1ora....C1.lsnr application ONLINE ONLINE rac1ora.rac1.gsd application ONLINE ONLINE rac1ora.rac1.ons application ONLINE O

[root@RAC1 ~]# uname -aLinux RAC1 2.6.9-89.0.28.ELsmp #1 SMP Fri Aug 20 16:11:59 EDT 2010 i686 i686 i386 GNU/Linux[root@RAC1 ~]# service vsftpd startu4e3a vsftpd u542fu52a8 vsftpduff1a500 OOPS: could not bind listening IPv4 socket [ u786eu5b9a ][root@RAC1 ~]# service vsftpd stopu5173u95ed vsftpduff1a [ u786eu5b9a ][root@RAC1 ~]# service vsftpd startu4e3a vsftpd u542fu52a8 vsftpduff1a

有人说做IT的不懂生活。有时想想好像也是，除了工作要对着计算机，回家也要对着电脑，只是做的事不同。工作是写代码或是其他相关的，回家忙着写blog，看电影或是玩游戏。其实这何尝不是一种生活呢，难道都要到外面去活动才能叫生活，只是大家生活方式不同而已，况且现在宅男宅女多的是，只要大家过得充实、快乐,方式其实并不重要！[@more@]

OS platform: RHEL/etc/init.d/iptables status --check firewall statussystem-config-securitylevel --config firewall[@more@]

首先利用DBCA创建模板文件test_dbca_silent，然后利用下面的命令创建数据库 in silent mode.C:windowssystem32>dbca -createDatabase -templateName "D:optoracleproduct10.2.0db_1assistantsdbcatemplatestest_dbca_silent.dbc" -gdbName jerry.cn -silent正在复制数据库文件1% 已完成3% 已完成11% 已完成18% 已完成26% 已完成37% 已完成正在创建并启动 Oracle 实例40% 已完成45% 已完成50% 已完成55% 已完成56% 已完成60% 已完成62% 已完成正在进行数据库创建66% 已完成70% 已完成73% 已完成85% 已完成96% 已完成100% 已完

silent mode install oracle software./runInstaller -record -destinationFile /tmp/install.rsp./runInstaller -responseFile /tmp/install.rsp -silentsilent mode install oracle database./dbca ORACLE DBCA创建数据库DBCA template迁移ＤＢ（做实验) －＞ＯＫ　　数据库软件版本需要相同,新的数据库中用户需要重新启用,即首先解锁用户,再重新设置密码.并且要创建PASSWORD FILE，否则远程SYSDBA登录不了.在创建template过程中，数据库会自动关闭，然后重启。DBCA图形界面DBCA silent(做实验)手动创建（做实验)ORACLE INSTANCEemctl s

时区NLS_DATE_FORMATv$timezone_names,current_date,dbtimezone,sessiontimezone,localtimestamp,current_timestampselect dbtimezone from dual; --database zoneselect sessiontimezone from dual; --current zoneselect * from v$timezone_names;timestamptimestamp with time zonetimestamp with local time zoneyear -4712 to 9999timezone_hour -12 to 14timzone_minute 00 to 59SQL> create table tt1(d1 date,d2 timestamp,d3 timestamp with time zone,d4 timestamp with local time zone);Table created.SQL> insert i

This is a test for my first technology blog![@more@]

Tasks of a Database Administrator Task 1: Evaluate the Database Server Hardware Task 2: Install the Oracle Database Software Task 3: Plan the Database Task 4: Create and Open the Database Task ...