Output or log queries generated by WordPress

the-queries.php

<?php
if ( defined( 'SAVEQUERIES' ) && SAVEQUERIES )
	add_action( 'wp_footer', 'the_queries' );

function the_queries() {
	global $wpdb;
	if ( defined( 'LOGQUERIES' ) && LOGQUERIES ) {
		foreach ( $wpdb->queries as $query )
			error_log( trim( $query[0] ) . "\n", 3, WP_CONTENT_DIR . '/debug.log' );
	} else {
		echo '<pre>';
		print_r( $wpdb->queries );
		echo '</pre>';
	}
}