create a basic php toggle filter for a mysql statement

I have an event calendar on a wordpress site. You can see it in action here: [login to view URL] I would like a checkbox toggle to be applied to the calendar so a user can hide or view items pulled from different categories. I want users to be able to select/unselect any items and then click on a link to update query and show a new calendar containing only the categories they select. Attached is a screenshot of what i am looking for visually. my name is alex, please address me directly in your pmb so I know you actually read this message. also note that the information stored on the events is held in two places, the default wp_posts db and a second one that holds event details. this is the sql statement that you would need to modify for the toggle $queryPost = "select * from wp_post_events AS post_detail JOIN $wpdb->posts AS post ON post_detail.post_id=[login to view URL] where post.post_status='publish' AND post.post_type='post' AND event_date='".$date."' order by timestamp ASC"; i basically want you to add to that a condition 'where classifieds_category_slug= (any of the actively toggled items)' id like this done ASAP, please do not bid if you are too busy to handle this in the near future.