How to check if a data exist in database in PHP? (MULTIPLE)

Question

I have a registeration form with the if statement:

$query = "SELECT `username` FROM `users` WHERE `username`='$username'";
$query_run = mysql_query($query);

if (mysql_num_rows($query_run)==1) 
{
    echo "Username already exist.";
}

The thing i want to do is checking also the "email" and "nickname" if they exist in database. How can i do that?

possible duplicate of [How to check if value already exists in MySQL database](http://stackoverflow.com/questions/8015098/how-to-check-if-value-already-exists-in-mysql-database) — Fibonacci, Feb 27 '14 at 15:25
Why do you throw mud to my question :D @Nouphal.M ty mate i tried it and it worked — Ozan Kurt, Feb 27 '14 at 15:32
Does this answer your question? [How to check if a row exists in MySQL? (i.e. check if an email exists in MySQL)](https://stackoverflow.com/questions/22252904/how-to-check-if-a-row-exists-in-mysql-i-e-check-if-an-email-exists-in-mysql) — Dharman, Jun 28 '20 at 21:40

score 1 · Answer 1 · edited Feb 27 '20 at 00:51

1

Try this,

SELECT `username`, `email`, `nickname`
FROM `users`
WHERE (`username` = '$username' OR
       `email` = '$username' OR
       `nickname` = '$username' )

edited Feb 27 '20 at 00:51

Tony

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answered Feb 27 '14 at 15:26

Krish R

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I solved it by myself... :P But anyway: Clear code... Thanks! – Ozan Kurt Feb 27 '14 at 15:33
Why * instead of just username, he/she just want to know whether user already exists or not – Bhavik Shah Feb 27 '14 at 15:36

score 1 · Answer 2 · edited Jun 28 '20 at 21:39

You should not use plain mysql_query

To quote php.net

Warning This extension is deprecated as of PHP 5.5.0, and will be removed in the future. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include: mysqli_query() PDO::query()

Try using PDO or mysqli. This is essential to prevent mysql injections.

http://php.net/manual/en/pdo.prepared-statements.php

Here is an example for how to do this with PDO

$config['db'] = array(
    'host'          => 'localhost',
    'username'      => 'username',
    'password'      => 'password',
    'dbname'        => 'dbname'
    );



$db = new PDO("mysql:host={$config['db']['host']};dbname={$config['db']['dbname']}",
              $config['db']['username'], $config['db']['password']);


$sql = "SELECT * FROM `users`";
$stmt = $db->prepare($sql);
$stmt->execute();

$users = $stmt->fetchAll()

$username = 'Bob';
$email = 'bob@gmail.com';
$nickname = 'BobTheMan';

foreach($users as $user)
{
    if($user['username'] == $username)
    {
        // there is a user by this username
    }
    if($user['email'] == $email)
    {
        // there is a user by this email
    }
    if($user['nickname'] == $nickname)
    {
        // there is a user by this nickname
    }
}

score 0 · Answer 3 · answered Feb 27 '14 at 15:25

0

Use prepared statements. And mysql_* has been deprecated
SELECT * instead of SELECT 'username' vill return you whole row and you can check all fields

answered Feb 27 '14 at 15:25

rinchik

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Why * instead of just `username`, he/she just want to know whether user already exists or not – Bhavik Shah Feb 27 '14 at 15:29
oh... after reading i thought that he wants to know if those fiedls are populated not that he wants to check username against those fields ) – rinchik Feb 27 '14 at 15:34
Bhavik Shah, he also want to know how to check if "email" and "nickname" exists in the database, and if he just grabs username, then email, then nickname he'll run 3 queries to the DB instead of grabbing all columns and then looping through them with PHP (with 1 querie) – oBo Feb 27 '14 at 15:52

score 0 · Answer 4 · edited Jun 28 '20 at 09:43

0

$result = $conn->query($sql);
if ($result->num_rows > 0) {
  print_r($result);
} else {
  echo "0 results";
}

edited Jun 28 '20 at 09:43

h3t1

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answered Jun 27 '20 at 13:01

Fazool Mohamed

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score -1 · Answer 5 · answered Feb 27 '14 at 15:28

// sql injection friendly code! *here*
$query = "SELECT `username` FROM `users`
    WHERE '$username' IN (`username`, `email`, `nickname`) LIMIT 1;";
$query_run = mysql_query($query);
if (mysql_num_rows($query_run) == 1){
    echo "Username already exist.";
}

I assume values are unique in users as you do == 1. Otherwise change == 1 to > 0 and remove LIMIT 1.

score -1 · Answer 6 · edited Feb 27 '14 at 15:42

-1

Expanding what Nouphal said.

$query = "SELECT `username` FROM `users` WHERE `username'=$username OR 'email' = $email";

edited Feb 27 '14 at 15:42

Funk Forty Niner

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answered Feb 27 '14 at 15:30

General_Twyckenham

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How to check if a data exist in database in PHP? (MULTIPLE)

6 Answers6