How to display database query statistics on WordPress site?

There are many ways to display database query statistics on WordPress site.

You can add following code to the bottom of the footer page:

<?php echo $wpdb->num_queries; ?> <?php _e('queries'); ?>. <?php timer_stop(1); ?> <?php _e('seconds'); ?>

Another code that can be used is:

<?php echo get_num_queries(); _e(' queries'); ?> in <?php timer_stop(1); _e(' seconds'); ?></p>