PHP连接Mysql数据库代码
<?php 
$mysql_server_name='localhost';//改成自己的mysql数据库服务器
$mysql_username='root';//改成自己的mysql数据库用户名
$mysql_password='888888';//改成自己的mysql数据库密码
$mysql_database='studyPhp';//改成自己的mysql数据库名

$conn=mysql_connect($mysql_server_name,$mysql_username,$mysql_password,$mysql_database); 
//以下为开始建立数据库及表，如果你已经有请略过此步
$sql='create database studyPhp default character set gbk collate gbk_chinese_ci; 
'; 
mysql_query($sql); 
$sql='create table `lwpcms_news` (`id` int(255) unsigned not null auto_increment,`title` int(255) unsigned not null default 0,`content` text,primary key ( `id` ) ) type = innodb;'; 
mysql_select_db($mysql_database,$conn); 
$result=mysql_query($sql); 
//echo $sql; 
mysql_close($conn); 
echo "Hello!数据库studyPhp已经成功建立！"; 
?>

PHP连接ACCESS数据库代码
<?
$conn = new com("ADODB.Connection"); 
$connstr = "DRIVER={Microsoft Access Driver (*.mdb)}; DBQ=". realpath("db1.mdb"); 
$conn->Open($connstr); 
$rs = new com("ADODB.RecordSet"); 
$rs->Open("select * from News",$conn,1,1); 
while(! $rs->eof) { 
$f = $rs->Fields(1); 
echo '<br />';
echo $f->value; 
$rs->MoveNext(); 
} 
?>

PHP连接MS SQL数据库代码
1.安装SQL服务器并添加PHP的MSSQL扩展
2.使用以下代码连接并测试
<?php 

$myServer = localhost; //主机
$myUser = sa; //用户名
$myPass = password; //密码
$myDB = Northwind;  //MSSQL库名

$s = @mssql_connect($myServer, $myUser, $myPass) 
or die(Couldnt connect to SQL Server on $myServer); 

$d = @mssql_select_db($myDB, $s) 
or die(Couldnt open database $myDB); 

$query = SELECT TitleOfCourtesy+ +FirstName+ +LastName AS Employee ; 
$query .= FROM Employees ; 
$query .= WHERE Country=USA AND Left(HomePhone, 5) = (206); 

$result = mssql_query($query); 
$numRows = mssql_num_rows($result); 

echo <h1> . $numRows . Row . ($numRows == 1 ? : s) . Returned </h1>; 

while($row = mssql_fetch_array($result)) 
{ 
echo <li> . $row[Employee] . </li>; 
} 

?>