What steps can be taken to troubleshoot and resolve errors related to mysql_num_rows in PHP?

The issue with mysql_num_rows in PHP can be resolved by checking if the result set returned by the query is valid before calling mysql_num_rows. This can be done by using functions like mysql_query or mysqli_query to execute the query and then checking if the result set is valid before calling mysql_num_rows.

// Execute the query
$result = mysqli_query($conn, "SELECT * FROM table");

// Check if the result set is valid
if($result) {
    // Get the number of rows
    $num_rows = mysqli_num_rows($result);
    
    // Use the result set
    while($row = mysqli_fetch_assoc($result)) {
        // Process each row
    }
} else {
    // Handle the error
    echo "Error executing query: " . mysqli_error($conn);
}