一、怎么样取得最新版本的MySQL? 要安装MySQL,首先要当然要取得它的最新版本,虽然大家都知道在FreeBSD的Packages中可以找到MySQL,但是我还是建议大家到网络上去找最新版本的MySQL。 二、安装MySQL时候的注意事项? 1、如果您是用MySQL+Apache,使用的又是
一、怎么样取得最新版本的MySQL?
要安装MySQL,首先要当然要取得它的最新版本,虽然大家都知道在FreeBSD的Packages中可以找到MySQL,但是我还是建议大家到网络上去找最新版本的MySQL。
二、安装MySQL时候的注意事项?
1、如果您是用MySQL+Apache,使用的又是FreeBSD网路操作系统的话,安装时候你应按注意到FreeBSD的版本问题,在 FreeBSD的3.0以下版本来说,MySQL Source内含的MIT-pthread运行是正常的,,但在这版本以上,你必须使用
native threads,也就是加入一个with-named-thread-libs=-lc_r的选项。
2、如果您在COMPILE过程中出了问题,请先检查你的gcc版本是否在2.81版本以上,gmake版本是否在3.75以上。
3、如果不是版本的问题,那可能是你的内存不足,请使用./configure -- with-low-memory来加入。
4、如果您要重新做你的configure,那么你可以键入rm config.cache和make clean来清除记录。
5、我们一般把MySQL安装在/usr/local目录下,这是缺省值,您也可以按照你的需要设定你所安装的目录。
三、启动和停止MySQL
如果你的机器上从未安装过MySQL的话,在安装MySQL时,最后一个键入的命令是/usr/local/mysql-3.23X/scripts/mysql_install_db
如果你是同时安装多台机器的话,你可以编辑一下这档案,这样一来可以使你方便的设置好每一台的权限。
1、在安装目录/usr/local启动mysql可以使用/usr/local/share/mysql/mysql.server start记得把mysql.server的属性设置成777
2、要停止mysql daemon可以使用/usr/local/bin/mysqladmin shutdown来实现
3、如果你的mysql已经设置了密码,你必须使用mysqladmin -u root -p shutdown来实现
四、用root建一个MYSQL的使用者
你需要先用root登入机器,然后改变目录存取权限chown -R mysql /usr/local/var,接着修改mysql.server 档案,这文件位于/usr/local/share/mysql/下,把mysql_daemon_user=root改成 mysql_daemon_user=mysql。
但是在以后新增资料库之后,记得把你的相关档案存取权限改过去:chown -R mysql /usr/local/var/some_new_dbs
如果你希望你的电脑启动时候自动加载mysql,你只要在/etc/rc.local加入一行/usr/local/mysql/share.server start
五、测试你的mysql
启动mysql后,你可以使用ps -aux来测试,你就发现多了两个process MYSQL使用的语法概观
字符串类型---STRINGS
字符串的匹配必须是成对的,例如:
‘MY IS OCP’
“MY IS OCPISCAI”
他们必须是是用‘’或“”来表示!
我们来举一些在字符串里面含有单引号和双引号的例子,例如:
重复双引号:
mysql>select “ hi! “ “ocp” “!”
->hi!”ocp”!
因为我们的HTML网络里含有许多的单引号和双引号,所以程序
在这里会遇到些因为单引号和双引号而出错的问题,所以要加以小心。
数字类型---NUMBERS
我们来看一些合法的数字表达方式:
7
777
-777
77.77
77.777
-777.7777o+7
资料库的命名问题,TATBLE、INDEX、COLUMN、以及ALIAS NAME 的命名原则数字可以做为字首,可以有底线,但是不能完全是数字。尽可能的避免使用$字符,在MYSQL里$字符是完全合法的,不过就是会和PHP混淆,所以尽量不使用的好。在命名里不能有“.”字符。ALIAS NAME可以使用256个字符,其它的长度一般都限制在60个字符内。你可以根据你的需要自己修改MYSQL_INSTALL_DB把你所需要修改的长度改一改,改的时候注意别改的太过夸张,MYSQL资料库是可以支持,但MYSQL的核心我没有试过,也许会出现错误。
数值函数:在数值函数出错的时候,传回的都是NULL
LOG10(X) :以10为底的LOG值
mysql>SELECT LOG (EXP(1));
->2.000000
EXP(X):传回E的X次方,其中E是NATURAL LOG 的底数。
FLOOR(X):传回小于等于X的最大整数。
CEILING(X):传回大雨等于X的最小整数。
ROUND(X):四舍五入到整数。
MOD(N,M) 或者 % :取N除以M的余数。
SIGN(X):X大于传回1,X等于0传回0,X小于0传回-1。
ABS(X):取绝对值。
ROUND(X,D):四舍五入到D位小数。D等于0则与ROUND(X)相同。
三角函数:
ATAN(X,Y):反三角函数
ATAN2(X,Y):反三角函数
LEAST(X,Y,。。。):至少两个参数,传回最小值。
GREATEST(X,Y,。。。):至少两个参数,传回最大值。
DEGREES(X):转换弧度(RADIAN)到度数。
RADIANS(X):转换度数到弧度

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