/PHP/How to check if username already exists in php

How to check if username already exists in php

$firstname = $_POST["firstname"];
$lastname = $_POST["lastname"];
$email = $_POST["email"];
$pass = $_POST["password"];

$check_email = mysqli_query($conn, "SELECT Email FROM crud where Email = '$email' ");
if(mysqli_num_rows($check_email) > 0){
    echo('Email Already exists');
}
else{
    if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $result = mysqli_query($conn, "INSERT INTO crud (Firstname, Lastname, Email, Password) VALUES ('$firstname', '$lastname', '$email', '$pass')");
}
    echo('Record Entered Successfully');
}

Source: stackoverflow.com

How to check user already exists in php

$sql = "SELECT username FROM table_name WHERE username='{$username}'";
$result = mysqli_query($con,$sql) or die("Query unsuccessful") ;
      if (mysqli_num_rows($result) > 0) {
        echo "Username is already exist";
      } else {
             ...............   
      }

Similar codes

10 votes223 views4 answers
In random order laravel
PHP Laravel
9 votes223 views3 answers
Laravel enum migration
PHP Laravel
1 vote241 views1 answer
Laravel env google smtp
PHP Laravel
0 vote212 views1 answer
Php make simple loop of number elevated to exponent without pow
PHP
1 vote202 views1 answer
Php echo and array to consle
PHP
3 votes206 views1 answer
Codeigniter check affected rows
PHP
0 vote217 views2 answers
Php json request get value of an array element
PHP
0 vote207 views2 answers
Jquery greater than or equal to
PHP
0 vote219 views1 answer
Laravel collection forget
PHP Laravel
6 votes209 views3 answers
Date_default_timezone_set(): timezone id
PHP