Why Does \"mysql_fetch_array() Expects Parameter 1 to Be Resource\" Error Occur, and How Can It Be Fixed?

mysql_fetch_array() Expects Parameter 1 to Be Resource Problem

This error occurs when the mysql_fetch_array() function is called with an invalid or non-existent resource as its first parameter. A resource in PHP is a special type of variable that represents an external resource, such as a database connection or a file handle.

In the provided code, the mysql_query() function is used to retrieve a result set from a database. If the query execution fails, the function will return false, which is a boolean value. When a boolean value is passed to mysql_fetch_array(), it will cause the error "mysql_fetch_array() expects parameter 1 to be resource."

To resolve this issue, add an error check after the mysql_query() call:

<code class="php">$result = mysql_query("SELECT * FROM student WHERE IDNO=".$_GET['id']);
if (!$result) {
    die('Invalid query: ' . mysql_error());
}</code>

If mysql_query() returns false, the error check will trigger and an error message will be displayed. With this error checking in place, the mysql_fetch_array() function will only be called if a valid result set has been retrieved from the database.

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