检查用户名是否已在mysql中存在的php写法_PHP

$username=$_REQUEST['username']; 
$password=$_REQUEST['password']; 
echo "
excute the insertUserInfo"; 
$con=mysqli_connect("localhost","root","","my_db"); 
$sql="SELECT * FROM user WHERE username='$username'"; 

ho "
this username aready exists"; } else { $sql="INSERT INTO user (username,password) VALUES ('$username','$password')"; if(!mysqli_query($con,$sql)) { echo "
Error".mysqli_error($con); } else { echo "
one record added"; } } 
 
建议不要用： 
 代码如下:

mysql_num_rows($result)
 
lt;pre name="code" class="html">