sql query details for a certain date - sql

Question

I have the following database:
create table Hotel (
HNo char(4),
Name varchar(20) not null,
Address varchar(50),
Constraint PK_Hotel Primary Key (HNo))
)
create table Room (
RNo char(4),
HNo char(4),
Type char(6) not null,
Price decimal (7,2),
Constraint PK_Room Primary Key (HNo, RNo),
Constraint FK_Room Foreign Key (HNo)
references Hotel (HNo)
)
create table Guest (
GNo char(4),
Name varchar(20) not null,
Address varchar(50),
Constraint PK_Guest Primary Key (GNo)
)
create table Booking (
HNo char(4),
GNo char(4),
DateFrom date,
DateTo date,
RNo char(4),
Constraint PK_Booking Primary Key (HNo, GNo, DateFrom),
Constraint FK_Booking Foreign Key (GNo)
references Guest (GNo),
Constraint FK_Booking_room Foreign Key (HNo, RNo)
references Room (HNo, RNo),
Constraint FK_Booking_hotel Foreign Key (HNo)
references Hotel (HNo)
)
What I am struggling with is using the dateto=> <=datefrom and getting it to work.
For the 26th march 1997, I need to list the details of all rooms in all hotels, including the name of any guests who were staying in the room. I'm not too bad with joining the tables etc, but am not sure how to do it as a whole on the specified date? Any ideas?

Answer 1

SELECT
h.Name,
h.Address,
r.RNo,
r.HNo,
r.Type,
r.Price,
G.Name,
G.Address,
...
FROM Hotel AS h
INNER JOIN Room AS r ON h.HNo = r.HNo
INNER JOIN Guest AS g ON r.RNo = g.RNo
INNER JOIN Booking AS b ON b.GNo = g.GNo
AND b.HNo = h.HNo
WHERE b.DateFrom <= #DateFrom
AND b.DateTo => #DateTo;

Answer 2

SELECT b.datefrom, b.dateto, h.name AS hotelname
, b.rno
, r.type
, g.name AS guestname
FROM booking b
JOIN hotel h ON b.hno = h.hno
JOIN guest g ON g.gno = b.gno
JOIN room r ON b.rno = r.rno
WHERE #yourDate BETWEEN b.datefrom AND b.dateto
EDIT :
Replace the #yourDate in the last line with a suitable expression supported by your DBMS.
E.g., in Oracle, there is a function TO_DATE which converts a given string to date, like TO_DATE('26-MAR-1997') BETWEEN b.datefrom AND b.dateto. In SQL Server there is CAST function.