Running functions inside of a view Oracle SQL - sql

Question

I'm trying to create a view that returns all the bookings that are between a certain date. I have a table called Booking which includes the columns:
startDate date,
noOfDays int,
and more columns which aren't relevant to the view I'm trying to create.
I'm trying to run the following query to create a view but it seems to fail with the error "ORA-00904: "DATEADD": Invalid identifier"
CREATE VIEW Present_bookings AS
SELECT * FROM Booking
WHERE startDate => '2018-03-12'
AND startDate <= DATEADD(Booking.startDate, 'YYYY-MM-DD', Booking.noOfDays);
What am I doing wrong?

Answer 1

The logic is not correct. All startdate is less than startdate+5 days. Are you sure about this condition? If yes, then it will be simplied as:
CREATE VIEW Present_bookings AS
select *
FROM Booking
where startDate >= to_date('2018-03-12','YYYY-MM-DD')
OR probably you are thinking about this:
CREATE VIEW Present_bookings AS
select *
FROM Booking
where startDate between to_date('2018-03-12','YYYY-MM-DD')
and to_date('2018-03-17','YYYY-MM-DD')

Answer 2

There are a couple of things wrong with your query. But the primary thing is that DATEADD() is not a valid function in Oracle. Oracle date arithmetic is very simple; just add noOfDays to startDate:
CREATE VIEW Present_bookings AS
SELECT * FROM Booking
WHERE startDate >= DATE'2018-03-12'
AND startDate <= startDate + noOfDays;
Note that I changed your operator => to >= and added the DATE keyword to the date literal 2018-03-12 to tell Oracle that it's a date.
As an aside, I don't know what the second condition is supposed to do; startDate should always be less than startDate + noOfDays unless noOfDays is negative. I think you might want something like the following:
CREATE VIEW Present_bookings AS
SELECT * FROM Booking
WHERE startDate <= DATE'2018-03-12'
AND DATE'2018-03-12' <= startDate + noOfDays;
OR
CREATE VIEW Present_bookings AS
SELECT * FROM Booking
WHERE DATE'2018-03-12' BETWEEN startDate AND startDate + noOfDays;

Answer 3

I guess you're looking for a easy way to add a number of days to a date.
Try using interval here:
select sysdate, sysdate + interval '5' day as "FUTURE" from dual;
=>
SYSDATE FUTURE
22.03.2018 14:37:27 27.03.2018 14:37:27
Take care of the '5' as a character, not a number.
This also works with years, months (take care of 29.02 here) etc.