PHP的常用数据操作(MYSQL)

刚学PHP整理一下，相关的数据操作。
1.PHP连接MYSQL数据库
mysql_connect([string hostname:port],[string username],[string password],[string databasename])
mysql_connect([string hostname:port],[string username],[string password])
demo:
//连接test数据库
$conn = mysql_connect('localhost','root','mypassword','test');
//结束
$conn = mysql_connect('localhost','root','mypassword');
mysql_select_db('test');
//结束

2.查询数据表
mysql_query([string sql])
demo:
//查询user表
$mysql = "select * from usertable order by id desc";
$result = mysql_query($mysql);
while ($row=mysql_fetch_array($result)){
          echo "用户名:".$row[username]."</br>";
}

3.更新记录
mysql_query([string update sql])

4.删除记录
mysql_query([string delete sql])