WITH RoomAmount AS ($($

SELECT

booking.id AS booking_$\_$id,$,$

COALESCE($($SUM($($rc.$.$base_$\_$price *$*$ DATEDIFF($($day,$,$ booking.checkin_$\_$date, booking.checkout_$\_$date)),0)$)),0)$ AS room_$\_$amount

FROM

booking

JOIN

booking_$\_$room br ON booking.id =$=$ br.$.$booking_$\_$id

JOIN

room r ON br.$.$room_$\_$id =$=$ r.$.$id

JOIN

room_$\_$class rc ON r.$.$room_$\_$class_$\_$id =$=$ rc.$.$id

GROUP BY

booking.id

),$),$

AddonAmount AS ($($

SELECT

booking.id AS booking_$\_$id,$,$

COALESCE($($SUM($($a.$.$price),0)$),0)$ AS addon_$\_$amount

FROM

booking

LEFT JOIN

booking_$\_$addon ba ON booking.id =$=$ ba.$.$booking_$\_$id

LEFT JOIN

addon a ON ba.$.$addon_$\_$id =$=$ a.$.$id

GROUP BY

booking.id

)$)$

UPDATE booking

SET booking_$\_$amount =$=$

($($

SELECT COALESCE($($SUM($($room_$\_$amount),0)+$),0)+$ COALESCE($($SUM($($addon_$\_$amount),0)$),0)$

FROM RoomAmount

FULL JOIN AddonAmount ON RoomAmount.booking_$\_$id =$=$ AddonAmount.booking_$\_$id

WHERE booking.id =$=$ RoomAmount.booking_$\_$id

)$)$; can you expalin this query in details ?$?$ also is there better way to do it in more comprehensive way ?$?$