If you've been working with PHP and MySQL, you may have come across the error message "mysql_fetch_array() expects parameter 1 to be resource" at some point. Don't worry, it's a common error and can be resolved with a few simple steps. In this guide, we'll go over what causes this error and how to fix it.
What Causes the Error?
This error occurs when the mysql_query() function fails to execute a query properly. The mysql_query() function returns false if the query fails, and this value is passed to the mysql_fetch_array() function as a parameter instead of the expected resource.
How to Fix the Error
To fix the error, you need to make sure that the mysql_query() function is executed properly and returns a valid resource. Here are some steps to follow:
Check the SQL Query - Make sure that the SQL query you're trying to execute is valid and doesn't contain any syntax errors. You can use a tool like phpMyAdmin to test your query and make sure it works.
Check the MySQL Connection - Make sure that you've established a valid MySQL connection before executing the query. You can use the mysql_connect() function to establish a connection, and the mysql_select_db() function to select the database you want to work with.
Check the mysql_query() Function - Make sure that the mysql_query() function is executed properly and returns a valid resource. You can use the mysql_error() function to check for any errors that might have occurred during the execution of the query.
Here's an example code snippet that demonstrates how to fix the error:
$link = mysql_connect('localhost', 'user', 'password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
$db_selected = mysql_select_db('database_name', $link);
if (!$db_selected) {
die ('Can\'t use database_name: ' . mysql_error());
}
$result = mysql_query('SELECT * FROM table_name', $link);
if (!$result) {
die('Invalid query: ' . mysql_error());
}
while ($row = mysql_fetch_array($result)) {
// Do something with the row data
}
mysql_close($link);
FAQ
Q1: What is the mysql_fetch_array() function?
A1: The mysql_fetch_array() function is a PHP function that fetches a row from a MySQL database and returns it as an array.
Q2: What is the mysql_query() function?
A2: The mysql_query() function is a PHP function that executes a MySQL query.
Q3: What is the mysql_connect() function?
A3: The mysql_connect() function is a PHP function that establishes a connection to a MySQL database.
Q4: What is the mysql_select_db() function?
A4: The mysql_select_db() function is a PHP function that selects a MySQL database to work with.
Q5: What is the mysql_error() function?
A5: The mysql_error() function is a PHP function that returns the error message from the last MySQL operation.