SELECT 
	BookingNumber,
	NewBookingNumber = 'B' + RIGHT ('00000000' + CAST (BookingNumber AS varchar (30)), 8)
FROM Bookings
WHERE BookingNumber = '0' 

USE Occupancy

;WITH BookingsToUpdate AS (
	SELECT 
		*,
		Seq = ROW_NUMBER() OVER (ORDER BY Booking_Skey)  
	FROM Bookings
)

SELECT
	Seq, 
	Booking_Skey,
	BookingNumber = 'B' + RIGHT('0000000' + CAST(Seq AS VARCHAR(8)),8),
	AnotherBookingNumber = 'B' + RIGHT('0000000' + CAST(Booking_Skey AS VARCHAR(8)),8)
FROM BookingsToUpdate