SQL Server-fråga:Använder JOIN för att inkludera NULL-värden

För att returnera eller producera NULL värden du måste använda LEFT JOIN s.

Så din fråga bör vara något i stil med:

SELECT 
     a.ReservationStayID AS 'Reservation Id'
    ,a.PMSConfirmationNumber AS 'PMS No'
    ,a.CreatedOn AS 'Date Created'
    ,a.ArrivalDate AS 'Date of Arrival'
    ,a.DepartureDate AS 'Date of Departure'
    ,a.TAProfileID AS 'TA Id'
    ,a.StatusCode AS 'Status'
    ,b.PropertyCode AS 'Hotel'
    ,c.NAME AS 'Travel Agency'
    ,c.CountryCode AS 'Market Code'
    ,d.CountryName AS 'Mkt'
FROM ReservationStay a
    INNER JOIN GuestStaySummary b ON a.ReservationStayID = b.ReservationStayID
    LEFT JOIN TravelAgency c ON a.TAProfileID = c.TravelAgencyID
    LEFT JOIN Market d ON c.CountryCode = d.CountryCode