PHP to check if the user name exists in MySQL

Source: Internet
Author: User

There are a number of ways to check if a user name exists in MySQL, and here's how to do it with PHP.

When you write the registration system, if you want to check the existence of the user name, PHP can write: The code is as follows: $username =$_request[' username '];  $password =$_request[' password '];  echo "<br/>excute the Insertuserinfo";  $con =mysqli_connect ("localhost", "root", "" "," my_db ");    $sql = "SELECT * from user WHERE username= ' $username '"; Ho "<br/>this username aready exists"; else {$sql = INSERT into User (Username,password) VALUES (' $username ', ' $password '); if (!mysqli_query ($con, $sql)) {Ech O "<br/>error". Mysqli_error ($con);    else {echo ' <br/>one record added ';}} Not recommended: Code as follows: Mysql_num_rows ($result) </pre> lt;pre name= "code" class= "HTML" ></pre>
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