mysql_fetch_array()/mysql_fetch_assoc()/mysql_fetch_row()/mysql_num_rows etc… expects parameter 1 to be resource

Question

I am trying to select data from a MySQL table, but I get one of the following error messages:

mysql_fetch_array() expects parameter 1 to be resource,

Answer 1

Try this code it work fine

assign the post variable to the variable

   $username = $_POST['uname'];

   $password = $_POST['pass'];

  $result = mysql_query('SELECT * FROM userData WHERE UserName LIKE $username');

if(!empty($result)){

    while($row = mysql_fetch_array($result)){
        echo $row['FirstName'];
     }
}

Answer 2

<?php
      $username = $_POST['username'];
       $password = $_POST['password'];

     $result = mysql_query("SELECT * FROM Users WHERE UserName LIKE '".mysql_real_escape_string($username)."'")or die(mysql_error());
while($row=mysql_fetch_array($result))
  {
 echo $row['FirstName'];
 }
 ?>

Answer 3

Usually an error occurs when your database conectivity fails, so be sure to connect your database or to include the database file.

include_once(db_connetc.php');

OR

// Create a connection
$connection = mysql_connect("localhost", "root", "") or die(mysql_error());

//Select database
mysql_select_db("db_name", $connection) or die(mysql_error());

$employee_query = "SELECT * FROM employee WHERE `id` ='".$_POST['id']."'";

$employee_data = mysql_query($employee_query);

if (mysql_num_rows($employee_data) > 0) {

    while ($row = mysql_fetch_array($employee_data)){
        echo $row['emp_name'];
    } // end of while loop
} // end of if

• Best practice is to run the query in sqlyog and then copy it into your page code.
• Always store your query in a variable and then echo that variable. Then pass to mysql_query($query_variable);.

Answer 4

Traditionally PHP has been tolerant to bad practice and failures in code, which makes debugging quite hard. The problem in this specific case is that both mysqli and PDO by default don't tell you, when a query failed and just return FALSE. (I will not talk about the depricated mysql extention. The support for prepared statements is reason anough to switch either to PDO or mysqli.) But you can change the default behavior of PHP to always throw exceptions when a query fails.

For PDO: Use $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

error_reporting(E_ALL);

$pdo = new PDO("mysql:host=localhost;dbname=test", "test","");
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

$result = $pdo->query('select emal from users');
$data = $result->fetchAll();

This will show you the following:

Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[42S22]: Column not found: 1054 Unknown column 'emal' in 'field list'' in E:\htdocs\test\mysql_errors\pdo.php on line 8

PDOException: SQLSTATE[42S22]: Column not found: 1054 Unknown column 'emal' in 'field list' in E:\htdocs\test\mysql_errors\pdo.php on line 8

As you see, it tells you exactly, what is wrong with the query, and where to fix it in your code.

Without $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); you will get

Fatal error: Call to a member function fetchAll() on boolean in E:\htdocs\test\mysql_errors\pdo.php on line 9

For mysqli: Use mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);

error_reporting(E_ALL);

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = new mysqli('localhost', 'test', '', 'test');

$result = $mysqli->query('select emal from users');
$data = $result->fetch_all();

You will get

Fatal error: Uncaught exception 'mysqli_sql_exception' with message 'Unknown column 'emal' in 'field list'' in E:\htdocs\test\mysql_errors\mysqli.php on line 8

mysqli_sql_exception: Unknown column 'emal' in 'field list' in E:\htdocs\test\mysql_errors\mysqli.php on line 8

Without mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT); you only get

Fatal error: Call to a member function fetch_all() on boolean in E:\htdocs\test\mysql_errors\mysqli.php on line 10

Of course, you could manually check the MySQL errors. But I would go crazy if I had to do that every time I made a typo - or worse - every time I want to query the database.

Answer 5

Try this, it must be work, otherwise you need to print the error to specify your problem

$username = $_POST['username'];
$password = $_POST['password'];

$sql = "SELECT * from Users WHERE UserName LIKE '$username'";
$result = mysql_query($sql,$con);

while($row = mysql_fetch_array($result))
{
    echo $row['FirstName'];
}

Answer 6

This error message is displayed when you have an error in your query which caused it to fail. It will manifest itself when using:

• mysql_fetch_array/mysqli_fetch_array()
• mysql_fetch_assoc()/mysqli_fetch_assoc()
• mysql_num_rows()/mysqli_num_rows()

Note: This error does not appear if no rows are affected by your query. Only a query with an invalid syntax will generate this error.

Troubleshooting Steps

• Make sure you have your development server configured to display all errors. You can do this by placing this at the top of your files or in your config file: error_reporting(-1);. If you have any syntax errors this will point them out to you.

• Use mysql_error(). mysql_error() will report any errors MySQL encountered while performing your query.

  Sample usage:

  mysql_connect($host, $username, $password) or die("cannot connect"); 
  mysql_select_db($db_name) or die("cannot select DB");
  
  $sql = "SELECT * FROM table_name";
  $result = mysql_query($sql);
  
  if (false === $result) {
      echo mysql_error();
  }
  

• Run your query from the MySQL command line or a tool like phpMyAdmin. If you have a syntax error in your query this will tell you what it is.

• Make sure your quotes are correct. A missing quote around the query or a value can cause a query to fail.

• Make sure you are escaping your values. Quotes in your query can cause a query to fail (and also leave you open to SQL injections). Use mysql_real_escape_string() to escape your input.

• Make sure you are not mixing mysqli_* and mysql_* functions. They are not the same thing and cannot be used together. (If you're going to choose one or the other stick with mysqli_*. See below for why.)

Other tips

mysql_* functions should not be used for new code. They are no longer maintained and the community has begun the deprecation process. Instead you should learn about prepared statements and use either PDO or MySQLi. If you can't decide, this article will help to choose. If you care to learn, here is good PDO tutorial.