If you have a web host or are working with a web host that severely limits the number of joins you can do in mysql, have not fear, there is a work around. Include the following code before your mysql query is executed.
If you are using Drupal and the Views module, which you should be, the problem is figuring out where to put this. I settled with adding it just before line 775 of view.inc inside the /views/includes/ directory. Putting the code here runs the statement above before evey views query is exectured. Let me know if there is a better way.
mysql_query('set SQL_BIG_SELECTS=1'); $result = db_query($query, $args);