文章列表
如果有一列的值为null，则数学运算结果就是null。
e.g.
select last_name, 12*salary*commission_pct from employees;
commission_pct为null的行，12*salary*commission_pct结果都是null
别名：
select last_name AS name, commission_pct comm from employees;
select last_name "Name", salary*12 "Annual Salary&quo ...
英语学术论文常用句型 Beginning 1. In this paper, we focus on the need for 2. This paper proceeds as follow. 3. The structure of the paper is as follows. 4. In this paper, we shall first briefly introduce fuzzy sets and related concepts 5. To begin with we will provide a brief background on t ...
I'm the one who make me see the morning sun
I'm the one who make me stand still on the ground
I can swim in the ocean
I can fly in the sky
I won't drown or fall anymore
Cos I'm not scared
I'm the moon of the night, shining thorough my eyes
I'm the beautiful rain when my heart is dry
And I kno ...
table=str.maketrans("abcdefghijklmnopqrstuvwxyz", "cdefghijklmnopqrstuvwxyzab")
orig="""g fmnc wms bgblr rpylqjyrc gr zw fylb. rfyrq ufyr amknsrcpq ypc dmp. \
bmgle gr gl zw fylb gq glcddgagclr ylb rfyr'q ufw rfgq rcvr gq qm jmle. \
sqgle qrpgle.kyicrpylq() gq ...
print(2**38)
结果:274877906944
1.
元宵节：
Lantern Festival
2.
刺绣：
embroidery
3.
重阳节：
Double-Ninth
Festival
4.
清明节：Tomb
sweeping day
5.
剪纸：
Paper Cutting
解决方案如下
用Ubuntu live启动进入Ubuntu
运行终端，输入命令：sudo fdisk
-l(在罗列出的计算机的盘符信息中找到Linux所在的盘符，如我的是在Dev/sda3)
再输入命令：sudo
-i(获取权限)
输入命令：mount /dev/sda3(数字为你的Ubuntu所在盘符) /mnt(注意空格不可少)
输入：grub-install --root-directory=/mnt /dev/sda
至此，Grub基本修复完毕。
（拔U盘）关机重启。熟悉的双系统Grub引导界面会出现，此时选择进入 ...
[前言]:
很久之前就想写一篇关于MLDonkey的文章, 一直没有动力, 今天趁着回父母家无事, 把关于我知道的MLdonkey的调教方法公布一下,
基本上所有内容都是从互联网上google以及整合出来的, 不需要高深的技巧, 尽量做到for dummies.
[ ...
Linux is for people who want to know why it works.
Mac is for
people who dont want to know why it works.
DOS is for people who
want to know why it does not work.
Windows is for people who dont
want to know why it does not work.
安装sun jdk
$ sudo vim /etc/apt/sources.list
添加源：
deb http://archive.canonical.com/ lucid partner
保存，然后：
$ sudo apt-get update
$ sudo apt-get install sun-java6-bin sun-java6-jre sun-java6-jdk
$ sudo apt-get install sun-java6-plugin
如果系统已经装了openjdk, 运行
$ sudo update-alternatives - ...