ALTER TABLE was_event_category
ADD COLUMN category_slug VARCHAR(100) AFTER category_name;

UPDATE was_event_category
SET category_slug = REPLACE(
	REPLACE(
		REPLACE(
			REPLACE(
				REPLACE(
					REPLACE(LOWER(category_name), ' ', '-')
					, ')', ''),
				 '(', ''),
			 '/', ''),
		 '&', ''),
	'--', '-');