php 通过php检查mysql表中是否存在用户名？
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Check if username exists in mysql table via php?
提问by Trevor Zucker
I am trying to figure out how to have my register php code check whether or not the registee's username is already taken, and if it is, don't register it, tell the user that it's taken. Here's my entire register processing file.
我想弄清楚如何让我的注册 php 代码检查注册者的用户名是否已经被占用，如果是，不要注册它，告诉用户它已被占用。这是我的整个寄存器处理文件。
<?php
$con=mysqli_connect("localhost","root","","users");
// Check connection
if (mysqli_connect_errno())
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
$hpassword = hash( 'sha512', $_POST['password'] );
$eusername = mysqli_real_escape_string( $con, $_POST['username'] );
$eemail = mysqli_real_escape_string( $con, $_POST['email'] );
$fusername = str_replace(' ', '', $eusername);
$sql="INSERT INTO users (username, password, email)
VALUES
('$fusername','$hpassword','$eemail')";
if (!mysqli_query($con,$sql))
{
die('Error: ' . mysqli_error($con));
}
mysqli_close($con);
?>
回答by Php developer
$sql=mysql_query("SELECT FROM users (username, password, email) WHERE username=$fusername");
if(mysql_num_rows($sql)>=1)
{
echo"name already exists";
}
else
{
//insert query goes here
}
you can check from database whether user exists and then paste the code
您可以从数据库中检查用户是否存在，然后粘贴代码
回答by Razeel Akbar
include ('database_connection.php');
if (isset($_POST['formsubmitted'])) {
$error = array();
if (empty($_POST['username'])) {
$error[] = 'Please Enter a name ';
} else {
$username = $_POST['username'];
}
if (empty($_POST['e-mail'])) {
$error[] = 'Please Enter your Email ';
} else {
if (filter_var($_POST['e-mail'], FILTER_VALIDATE_EMAIL)) {
//for email validation (refer: http://us.php.net/manual/en/function.filter-var.php)
$email = $_POST['e-mail'];
} else {
$error[] = 'Your EMail Address is invalid ';
}
}
if (empty($_POST['password'])) {
$error[] = 'Please Enter Your Password ';
} else {
$password = $_POST['password'];
}
if (empty($error))
{ // If everything's OK...
$query = "SELECT * FROM members WHERE username ='$username'";
$result = mysqli_query($dbc, $query); // here $dbc is your mysqli $link
if (!$result) {
echo ' Database Error Occured ';
}
if (mysqli_num_rows($result) == 0) { // IF no previous user is using this username.
$query = "INSERT INTO `members` ( `username`, `email`, `password`) VALUES ( '$name', '$email', '$password')";
$result = mysqli_query($dbc, $query);
if (!$result) {
echo 'Query Failed ';
}
if (mysqli_affected_rows($dbc) == 1) { //If the Insert Query was successfull.
// Send an email
// Finish the page:
echo '<div class="success">Thank you for registering! A confirmation email has been sent to ' . $email . ' Please click on the Activation Link to Activate your account </div>';
} else { // If it did not run OK.
echo '<div class="errormsgbox">You could not be registered due to a system error. We apologize for any inconvenience.</div>';
}
} else { // The username is not available.
echo '<div class="errormsgbox" >That username has already been registered.
</div>';
}
} else { //If the "error" array contains error msg , display them.... e.g....
echo '<div class="errormsgbox"> <ul>';
foreach ($error as $key => $values) {
echo ' <li>' . $values . '</li>';
}
echo '</ul></div>';
}
mysqli_close($dbc); //Close the DB Connection
} // End of the main Submit conditional.
回答by SoWhat
Either you can use Dave's way and check' the error code, or you can precheck whether the user exists
您可以使用 Dave 的方式检查错误代码，也可以预先检查用户是否存在
$sql="SELECT FROM users (username, password, email) WHERE username=$fusername"
Now check the results of this. If a row is fetched, then the user exists. Indicate this to the user. If not, the sun is shining on the user. Give him a cookie
现在检查这个结果。如果获取了一行，则该用户存在。向用户表明这一点。如果没有，太阳就照在用户身上。给他一块饼干
