Getting truly unique quotes with Srini G's Quotes Collection plugin for WordPress

quotes-collection.php

<?php

/** 
 * The Quotes Collection plugin, downloadable at http://wordpress.org/plugins/quotes-collection/,
 * is a great plugin. I've used it on a couple of client sites and it's simple to use.
 * However, there exists one little problem. If you want to show more than one quote
 * on a page, and you want those quotes to be different every time, there's no way to do 
 * that. Replace the quotescollection_get_quote() function in quotes-collection.php with 
 * my modified version below. Specifically, this guarantees that the quotes are truly random, 
 * and that once served on a page, you will not get the same quote again. To prove this in
 * action, go to your theme's functions.php file and paste this in:
 
  for ( $i = 0; $i < 10; $i++)
  {
    quotescollection_quote('show_source=true&ajax_refresh=false'); 
  }
 
 * This will print 10 unique quotes to the screen, assuming you have that many in WordPress.
 * 
 * I've asked Scrini to incorporate this (or something similar) to the live repository, but 
 * he's never gotten back with me. I've had to write this code twice now, so I'm finally
 * creating a Gist out of it. Google my name if you have trouble with it — you'll find me
 * easily enough.
 */

function quotescollection_get_quote( $condition = '', $random = 1, $current = 0 )
{
	static $used_ids = array();
	global $wpdb;
	$sql = "SELECT quote_id, quote, author, source
		FROM " . $wpdb->prefix . "quotescollection";
	if ( $condition )
  	{
	  $sql .= $condition;
  	}
	if( ! $random ) 
	{
		if ( $current )
  		{
			$sql .= " AND quote_id < {$current}";
		}
		$sql .= " ORDER BY quote_id DESC";
	}
	else
	{
		if ( count( $used_ids ) > 0 )
		{
			$sql .= ' AND quote_id !=';
			for ( $i = 0; $i < count( $used_ids ); $i++ )
			{
				$sql .= $used_ids[ $i ] . " ";
				if ( ( $i + 1 ) != count( $used_ids ) )
				{
					$sql .= 'AND quote_id !=';
				}
			}
		}
		$sql .= " ORDER BY RAND( " . rand() . ")";
	}
	$sql .= " LIMIT 1";

	$random_quote = $wpdb->get_row( $sql, ARRAY_A );

	array_push( $used_ids, $random_quote['quote_id'] );
	if ( empty( $random_quote ) ) 
  	{
		if ( ! $random && $current )
  		{
			return quotescollection_get_quote( $condition, 0, 0 );
    		}
		else
    		{
			return 0;
    		}
	}
	else
	{	
		return $random_quote;
	}
}