Plugin delete-revision worked fine after I tweaked the code with a different sql query. See this page:
Also, I tweaked my WordPress wp-config.php file to limit my future revision saves.
/* Specify levels of revision to retain. Or turn it off altogether with "false" */ define('WP_POST_REVISIONS', 3); // Limit post revisions.
There's a number of constants that can be entered in the wp-config.php which streamline WordPress's native activities.