未定义的索引php mysql错误[关闭]

I keep on getting this error message on this line of code with MySQL:

$result = mysql_query("select * from registered_payee 
                       WHERE customer_id='$_SESSION[customer_id]'");

how can i fix this while its inside a query?

Thanks.

original code:

<?php
session_start();
include("header.php");
include("dbconnection.php");
$result = mysql_query("select * from registered_payee WHERE customer_id='$_SESSION[customer_id]'");
$result1 = mysql_query("select * from registered_payee WHERE sl_no='$_POST[payto]'");
$arrpayment = mysql_fetch_array($result1);
$dt = date("Y-m-d h:i:s");
$acc= mysql_query("select * from accounts where customer_id='$_SESSION[customer_id]'");
?>

i guess you have problem with quotation .try this

   $result = mysql_query("select * from registered_payee 
                           WHERE customer_id='".$_SESSION['customer_id']."' ");

Obs:

• make sure to escape your values before inserting them to your query.

• and make sure to change from mysql to mysqli or pdo as mysql is deprecated.

You are using a constant in an associative element of an array, instead of a simple string:

"... '$_SESSION[customer_id]'"
                ^         ^

Plus, you don't escape the array properly:

"... '$_SESSION[customer_id]'"
      ^                    ^

So both mistakes fixed it should look like:

"... '" . $_SESSION['customer_id'] . "'"

Note: You should never put variables into strings without seperating them visually, to make it even more readable (more readable = faster error detection), put every part on a new line.

Using prepared statements (MySQLi, PDO), you can also avoid deprecated warnings and quotation mistakes.

To make the difference even more clear, try the following PHP snippet:

<?php
define('customer_id', 1);
$test['customer_id'] = 'with quotes';
$test[customer_id]   = 'without quotes';
print_r($test)