The thing is - you're forgetting to set proper delimiter. Your first syntax contains multiple operators inside trigger - and they need to be delimited by ;
- but you're not changing global delimiter - thus, MySQL treats that as syntax end - and, therefore, that's an error (because trigger isn't completed, obviously).
Your second syntax is executed completely since it has only one operator (and that stands for trigger end as well) - you've not enclosed it by BEGIN..END
To fix the issue, just do:
DELIMITER //
CREATE TRIGGER Trans_SubCategory_update AFTER UPDATE ON Trans_SubCategory
FOR EACH ROW
BEGIN
IF NEW.ts != OLD.ts THEN
INSERT INTO Sync_activities (table_name,table_id,admin_id,action) VALUES ('Trans_SubCategory', NEW.id, NEW.admin_id,'update');
END IF;
END;//
DELIMITER ;