Question

    CREATE TABLE "Reservation"(

    ReservationID int IDENTITY (1,1) NOT NULL,
    CustomerID int NOT NULL,
    RoomNo int NOT NULL,
    CheckInDate date NULL,
    CheckOutDate date NULL,
    NoOfDays int NULL,

    CONSTRAINT PK_Reservation PRIMARY KEY(ReservationID),

    CONSTRAINT FK_Reservation_Customers_CustID FOREIGN KEY(CustomerID)  
        REFERENCES dbo.Customers(CustomerID),

    CONSTRAINT FK_Reservation_Rooms_RoomNo FOREIGN KEY(RoomNo)
        REFERENCES dbo.Rooms(RoomNo)
)


INSERT Reservation(CustomerID,RoomNo,CheckInDate,CheckOutDate,NoOfDays)
        VALUES(1,101,'2012-01-01','2012-01-30',DATEDIFF(NoOfDays,'CheckInDate','CheckOutDate'))

Can someone please tell me how i can calculate the number of days between “CheckInDate” and “CheckOutDate” then have this value in the insert statement for NoOfDays. It’s hard to explain i hope you understood what i’m trying to achieve here.

Answer 1

UPDATED:

Try this:

INSERT Reservation(CustomerID,RoomNo,CheckInDate,CheckOutDate,NoOfDays)
    VALUES(1,101,'2012-01-01','2012-01-30',DATEDIFF(day,'2012-01-01','2012-01-30'));

SQL Fiddle