一、没有进行预处理的SQL语句
  <?php
  // 1.连接数据库
  $conn = mysql_connect('127.0.0.1:3306', 'root', '518666');
  if (!$conn)
  {
  die("Could not connect:" . mysql_error());
  }
  // 2.选择数据库
  mysql_select_db('mysql_safe', $conn);
  // 3.设置编码,注意这里是utf8而不是utf-8,如果写后者,MySQL不会识别的,会出现乱码的。
  mysql_query("SET NAMES utf8");
  $title    = "我们的爱情";
  $content  = '你是/谁啊,大几都"老梁"做做&>women<a>没';
  $add_time = date("Y-m-d H:i:s");
  // 转义字符
  $content = mysql_real_escape_string($content);
  $content = htmlspecialchars($content, ENT_COMPAT);
  // 你是/谁啊,大几都做做&>women<a>没   // 自动过滤反斜杠
  /*
  // 4.插入一条数据
  $insert_sql = "insert into post_tbl (title, content, user_id, add_time) values ('{$title}', '{$content}', '4742551', '{$add_time}')";
  if(mysql_query($insert_sql))
  {
  echo 'ok';
  }
  else
  {
  echo "Error : " . mysql_error();
  }
  $ret = mysql_affected_rows();
  print_r($ret);
  */
  // 5.PDO预处理插入
  // PDO(PHP Data Object)则是提供了一个 Abstraction Layer 来操作数据库
  // 查询
  $user_id  = 174742;
  $password = "''or '1=1'" ;
  $sql = "select * from post_tbl where user_id = {$user_id} and password = {$password}";
  print_r($sql);
  $query  = mysql_query($sql);
  // $result = mysql_fetch_array($query);
  $rows = array();
  while($row=mysql_fetch_array($query))
  {
  $rows[] = $row;
  }
  print_r( $rows);
  // 关闭数据库连接
  mysql_close($conn);
  /*
  $str = "Bill & 'Steve'";
  echo htmlspecialchars($str, ENT_COMPAT); // 只转换双引号
  echo "<br>";
  echo htmlspecialchars($str, ENT_QUOTES); // 转换双引号和单引号
  echo "<br>";
  echo htmlspecialchars($str, ENT_NOQUOTES); // 不转换任何引号
  */
  /*
  以上代码的 HTML 输出如下(查看源代码):
  Bill & 'Steve'<br>
  Bill & 'Steve'<br>
  Bill & 'Steve'
  以上代码的</a><a href="/lanqi" target="_blank" class="infotextkey">浏览器</a>输出:
  Bill & 'Steve'
  Bill & 'Steve'
  Bill & 'Steve'
  */
  function mforum_html_tag_to_html_entity($content)
  {
  $content = (string)trim($content);
  if(empty($content)) return '';
  // $content = str_replace(' ', ' ', $content);
  $content = htmlspecialchars($content, ENT_COMPAT, GB2312, false);
  $content = str_replace(">", ">", $content);
  $content = str_replace("<", "<", $content);
  $content = str_replace(""", """, $content);
  $content = preg_replace("/\$/", "$", $content);
  $content = preg_replace("/ /", "", $content);
  $content = str_replace("!", "!", $content);
  $content = str_replace("'", "'", $content);
  $content = preg_replace("/\/", "", $content);
  // 内容敏感词过滤
  return $content;
  }
  </code>
  二、PDO处理的SQL语句
  <?php 
  // PDO的使用
  // http://blog.csdn.net/qq635785620/article/details/11284591
  $dbh = new PDO('mysql:host=127.0.0.1:3306;dbname=mysql_safe', 'root', '518666');
  $dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);   
  $dbh->exec('set names utf8');  
  $title    = "我们的爱情";
  $content  = '你是/谁啊,大几都"老梁"做做&>women<a>没' . " 测试打印号'我是单引号'哈哈";
  $user_id  = 174742;
  $add_time = date("Y-m-d H:i:s");
  // $insert_sql = "insert into post_tbl (title, content, user_id, add_time) values (:x_title, :x_content, :x_user_id, :x_add_time)";
  // $stmt = $dbh->prepare($insert_sql);
  // $stmt->execute(array('x_title'=>$title,':x_content'=> $content, ':x_user_id' => $user_id, ':x_add_time' => $add_time));   
  // 查询
  $user_id  = "17474#";
  // $password = "''or '1=1'";
  $password = 123456;
  $sql = 'select * from post_tbl where user_id = :x_user_id and password = :x_password';
  $stmt = $dbh->prepare($sql);   
  $stmt->execute(array(':x_user_id'=>$user_id, ':x_password' => $password));   
  $rows = array();
  while($row = $stmt->fetch(PDO::FETCH_ASSOC))
  {  
  $rows[] = $row;   
  }  
  print_r($rows);   
  // echo $dbh->lastinsertid();   
  </a></code>