I want show only data for today

Well dear thanks for your effort.I solved this .here is answer.

$user1 = $wpdb->get_results("select product,checked_by,submit_date,unit_data,temperature_in,temperature_out,time_in,category from diary_user_form_storage  where category_name="opening" and DATE(`submit_date`) = CURDATE()");  

error code: 523