<?xml version="1.0" encoding="utf-8" ?><rss version="2.0"><channel><title><![CDATA[Studying . Working . A better life!]]></title><description><![CDATA[欢迎来到我的博客，如果对你有帮助，请评论，我将会做的更好，谢谢你的光临！]]></description><link>https://blog.youkuaiyun.com/emjava</link><language>zh-cn</language><generator>https://blog.youkuaiyun.com/</generator><copyright><![CDATA[Copyright &copy; emjava]]></copyright><item><title><![CDATA[SQL性能优化]]></title><link>https://blog.youkuaiyun.com/emjava/article/details/12080389</link><guid>https://blog.youkuaiyun.com/emjava/article/details/12080389</guid><author>emjava</author><pubDate>Fri, 27 Sep 2013 09:21:59 +0800</pubDate><description><![CDATA[1. 如何取数据：更快得取数据的方法：
   1）.有没用到索引 ;
   2）.取得字段是否足够少 ;
   3）.索引的顺序是否考虑周全 .
2. 如何运算 
   1）能少取1次数据就少取1次 ;
   2）运算过程中，能用oracle的API分析函数，就要用oracle的函数，不要自己造一个函数。所以一定要熟悉oracle 分析函数的API ;
   3）排序语句，能不用就不]]></description><category></category></item><item><title><![CDATA[oracle中冒号的问题 oracle中变量的绑定]]></title><link>https://blog.youkuaiyun.com/emjava/article/details/12065095</link><guid>https://blog.youkuaiyun.com/emjava/article/details/12065095</guid><author>emjava</author><pubDate>Thu, 26 Sep 2013 18:46:36 +0800</pubDate><description><![CDATA[在oracle中。"："有2中意思；

一：给变量赋值， 如， names varchar2(10) :='aa'; 这是把"aa"赋值给变量names

二：表示引用。即引用表中字段所对应的值

如：emp表中有个name为“Bob”，那么 : old.name 的值就是"Bob"。

只是表示引用的时候，只能出现在触发器里面。

希望对你有帮助！




http]]></description><category></category></item><item><title><![CDATA[ORACLE 中写入txt文本与从Txt文件中读入数据 修改表结构]]></title><link>https://blog.youkuaiyun.com/emjava/article/details/12050761</link><guid>https://blog.youkuaiyun.com/emjava/article/details/12050761</guid><author>emjava</author><pubDate>Thu, 26 Sep 2013 14:47:43 +0800</pubDate><description><![CDATA[--创建一个表
DROP TABLE TEST CASCADE CONSTRAINTS ;
CREATE TABLE TEST(A VARCHAR(30),B VARCHAR(30));
--查看具体的权限
SELECT DISTINCT PRIVILEGE FROM DBA_SYS_PRIVS WHERE PRIVILEGE LIKE '%DIRECTORY%';
--用SYS用户授权]]></description><category></category></item><item><title><![CDATA[PLSQL首先项中的键配置备份]]></title><link>https://blog.youkuaiyun.com/emjava/article/details/12014035</link><guid>https://blog.youkuaiyun.com/emjava/article/details/12014035</guid><author>emjava</author><pubDate>Wed, 25 Sep 2013 14:57:01 +0800</pubDate><description><![CDATA[PrefAutomaticStatistics=True
SelectedStatNames=
StoreHistory=True
HistorySize=8
DisplaySize=30
HistoryWithPassword=True
BackupFiles=3
BackupRelPath=Backup
BackupAbsPath=D:\bak备份文件
AutoSaveDes]]></description><category></category></item><item><title><![CDATA[oracle 中处理标准差的问题]]></title><link>https://blog.youkuaiyun.com/emjava/article/details/11927497</link><guid>https://blog.youkuaiyun.com/emjava/article/details/11927497</guid><author>emjava</author><pubDate>Mon, 23 Sep 2013 13:26:52 +0800</pubDate><description><![CDATA[Stddev返回expr的样本标准偏差。它可用作聚集和分析函数。
它与stddev_samp的不同之处在于，当计算的输入数据只有一行时，stddev返回0，而stddev_samp返回null。


SELECT STDDEV(T.TWRR) , stddev_samp(t.twrr) FROM TMP_TKZC_TWRR T;]]></description><category></category></item><item><title><![CDATA[Oracle中的数据类型转换函数 Cast(,)]]></title><link>https://blog.youkuaiyun.com/emjava/article/details/11742597</link><guid>https://blog.youkuaiyun.com/emjava/article/details/11742597</guid><author>emjava</author><pubDate>Mon, 16 Sep 2013 17:32:16 +0800</pubDate><description><![CDATA[CAST
将某种数据类型的表达式显式转换为另一种数据类型。
语法：
CAST ( expression AS data_type )
CAST(ytd_sales AS char(20))
举例：
declare @i int
set @i=0
while @i
begin
print char(ascii('a')+@i)+'的ASCII码是：'+cast(ascii('a']]></description><category></category></item><item><title><![CDATA[ORACLE PL/SQL编程之PL/SQL 流程控制语句]]></title><link>https://blog.youkuaiyun.com/emjava/article/details/11720343</link><guid>https://blog.youkuaiyun.com/emjava/article/details/11720343</guid><author>emjava</author><pubDate>Mon, 16 Sep 2013 09:08:59 +0800</pubDate><description><![CDATA[本篇主要内容如下：

　　3.1  条件语句

　　3.2  CASE 表达式

　　3.3  循环

　　3.4  标号和GOTO

　　3.5  NULL 语句

　　介绍PL/SQL的流程控制语句, 包括如下三类: 

　　控制语句: IF 语句 

　　循环语句: LOOP语句, EXIT语句 

　　顺序语句: GOTO语句, NULL语句

3.]]></description><category></category></item><item><title><![CDATA[pl/sql 设置快捷键]]></title><link>https://blog.youkuaiyun.com/emjava/article/details/11639303</link><guid>https://blog.youkuaiyun.com/emjava/article/details/11639303</guid><author>emjava</author><pubDate>Fri, 13 Sep 2013 13:01:53 +0800</pubDate><description><![CDATA[1、比如输入一个S加空格自动弹出 SELECT * FROM 
步骤： 菜单栏： 工具--》首选项-》编辑器
  右边 AutoReplace 点击‘Edit’  输入 s =SELECT * FROM 
2、关键字大写]]></description><category></category></item><item><title><![CDATA[oracle 学习笔记]]></title><link>https://blog.youkuaiyun.com/emjava/article/details/11599663</link><guid>https://blog.youkuaiyun.com/emjava/article/details/11599663</guid><author>emjava</author><pubDate>Thu, 12 Sep 2013 13:13:21 +0800</pubDate><description><![CDATA[一：oracle语法（20130906）
1.语法： 语法NULLIF ( expression1, expression2
)




语法NULLIF ( expression1 , expression2 )
参数expression1,expression2
如果两个表达式不相等，NULLIF 返回第一个 expression1 的值。
如果两个表达式相等，NULLIF]]></description><category></category></item><item><title><![CDATA[oracle 查看包是否已经存在]]></title><link>https://blog.youkuaiyun.com/emjava/article/details/11593779</link><guid>https://blog.youkuaiyun.com/emjava/article/details/11593779</guid><author>emjava</author><pubDate>Thu, 12 Sep 2013 10:18:41 +0800</pubDate><description><![CDATA[用PLsql打开一个命令窗口输入: SQL> view PKG_REPORT_TKZC_ANALYSE_DYX ;]]></description><category></category></item><item><title><![CDATA[在百度上回答的一个问题，修改之后  JS倒计时]]></title><link>https://blog.youkuaiyun.com/emjava/article/details/6846641</link><guid>https://blog.youkuaiyun.com/emjava/article/details/6846641</guid><author>emjava</author><pubDate>Thu, 06 Oct 2011 11:46:57 +0800</pubDate><description><![CDATA[String path = request.getContextPath();
 String basePath = request.getScheme() + "://"
   + request.getServerName() + ":" + request.getSer]]></description><category></category></item><item><title><![CDATA[谈谈你对流行框架的理解]]></title><link>https://blog.youkuaiyun.com/emjava/article/details/6845680</link><guid>https://blog.youkuaiyun.com/emjava/article/details/6845680</guid><author>emjava</author><pubDate>Wed, 05 Oct 2011 20:04:40 +0800</pubDate><description><![CDATA[1、谈谈你对Struts的理解。
答: 
1. struts是一个按MVC模式设计的Web层框架，其实它就是一个大大的servlet，这个Servlet名为ActionServlet，或是ActionServlet的子类。我们可以在web.xml文件中将符合某种特征的所有请求]]></description><category></category></item><item><title><![CDATA[三种数据库的分页语句]]></title><link>https://blog.youkuaiyun.com/emjava/article/details/6845655</link><guid>https://blog.youkuaiyun.com/emjava/article/details/6845655</guid><author>emjava</author><pubDate>Wed, 05 Oct 2011 19:54:52 +0800</pubDate><description><![CDATA[取出sql表中第31到40的记录（以自动增长ID为主键）
sql server方案1：
    select top 10 * from twhere id not in (select top 30 id from t order by id ) orde by id
s]]></description><category></category></item><item><title><![CDATA[判断输入框输入的是否是数字，不是则阻止提交]]></title><link>https://blog.youkuaiyun.com/emjava/article/details/6845642</link><guid>https://blog.youkuaiyun.com/emjava/article/details/6845642</guid><author>emjava</author><pubDate>Wed, 05 Oct 2011 19:42:17 +0800</pubDate><description><![CDATA[String path = request.getContextPath();
 String basePath = request.getScheme() + "://"
   + request.getServerName() + ":" + request.getSer]]></description><category></category></item><item><title><![CDATA[用table显示n条记录，每三条换一下颜色]]></title><link>https://blog.youkuaiyun.com/emjava/article/details/6845629</link><guid>https://blog.youkuaiyun.com/emjava/article/details/6845629</guid><author>emjava</author><pubDate>Wed, 05 Oct 2011 19:35:09 +0800</pubDate><description><![CDATA[String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+pat]]></description><category></category></item><item><title><![CDATA[判断第二个日期比第一个日期大]]></title><link>https://blog.youkuaiyun.com/emjava/article/details/6845622</link><guid>https://blog.youkuaiyun.com/emjava/article/details/6845622</guid><author>emjava</author><pubDate>Wed, 05 Oct 2011 19:31:04 +0800</pubDate><description><![CDATA[String path = request.getContextPath();
 String basePath = request.getScheme() + "://"
   + request.getServerName() + ":" + request.getSer]]></description><category></category></item><item><title><![CDATA[工厂设计类、代理设计]]></title><link>https://blog.youkuaiyun.com/emjava/article/details/6845613</link><guid>https://blog.youkuaiyun.com/emjava/article/details/6845613</guid><author>emjava</author><pubDate>Wed, 05 Oct 2011 19:23:19 +0800</pubDate><description><![CDATA[interface Fruit {
         public void eat() ;       // 目的就是吃
}
class Apple implements Fruit {
         public void eat(){]]></description><category></category></item><item><title><![CDATA[一个简单的单例设计]]></title><link>https://blog.youkuaiyun.com/emjava/article/details/6845607</link><guid>https://blog.youkuaiyun.com/emjava/article/details/6845607</guid><author>emjava</author><pubDate>Wed, 05 Oct 2011 19:20:06 +0800</pubDate><description><![CDATA[class Singleton {
         private final static Singleton INSTANCE = new Singleton() ;         // 实例化本类对象
         private Singleton(){}]]></description><category></category></item><item><title><![CDATA[取得指定文件里面的内容]]></title><link>https://blog.youkuaiyun.com/emjava/article/details/6845605</link><guid>https://blog.youkuaiyun.com/emjava/article/details/6845605</guid><author>emjava</author><pubDate>Wed, 05 Oct 2011 19:17:05 +0800</pubDate><description><![CDATA[1,张三,28
2,李四,35
3,张三,28
4,王五,35
5,张三,28
6,李四,35
7,赵六,28
8,田七,35

 
 
 
package cn.javase.util;
 
import java.io.BufferedReader]]></description><category></category></item><item><title><![CDATA[统计一个字符中中文，英文，数字出现的次数]]></title><link>https://blog.youkuaiyun.com/emjava/article/details/6845600</link><guid>https://blog.youkuaiyun.com/emjava/article/details/6845600</guid><author>emjava</author><pubDate>Wed, 05 Oct 2011 19:11:48 +0800</pubDate><description><![CDATA[package cn.javase.util;
public class NumTest {
 public static void main(String[] args) {
   
  String str = "4234nm4n234bbnm4b2m" ;]]></description><category></category></item></channel></rss>