SQL Server: check if certain date in calendar table falls on a weekend - sql

Question

I have created a calendar table that contains all the calendar dates of a year, incl. the corresponding quarter / week / month / day etc. information.
The following Select gives me a specific date, here the 17th of March.
How can I extend the below to check if this falls on a Saturday or Sunday (weekDayCal = 7 or 1) and, if true, return the date for the following Monday, otherwise return the 17th ?
SELECT *
FROM Calendar
WHERE (yearCal = 2014) AND (monthCal = 3) AND (dayCal = 17)
Many thanks in advance for any help with this, Mike.

Answer 1

Assuming you have a day_of_calendar style id field, where every date is sequentially in order, then this works...
SELECT *
FROM Calendar
WHERE id = (SELECT id + CASE weekDayCal WHEN 7 THEN 2 WHEN 1 THEN 1 ELSE 0 END
FROM Calendar
WHERE (yearCal = 2014) AND (monthCal = 3) AND (dayCal = 17)
)
If not, then you're going to have to return to using dates in one way or another.
For example...
SELECT *
FROM Calendar
WHERE realDate = (SELECT realDate + CASE weekDayCal WHEN 7 THEN 2 WHEN 1 THEN 1 ELSE 0 END
FROM Calendar
WHERE (yearCal = 2014) AND (monthCal = 3) AND (dayCal = 17)
)
But then you may as well just use real date calculations.

Answer 2

I think this should work, if you do indeed have a weekDayCal column where 1=Sunday, 2 = Monday and 7 = Saturday:
SELECT *
FROM Calendar
WHERE (yearCal = 2014) AND (monthCal = 3) AND (
(dayCal = 17 and weekDayCal not in (1,7)) OR
(dayCal = 17 + 1 and weekDayCal = 2) OR
(dayCal = 17 + 2 and weekDayCal = 2))

Answer 3

This fetches rows who fall on sunaday or saturday
SELECT *
FROM Calender
WHERE DATEPART(dw, CAST(
CAST(monthCal as VARCHAR(2))+ '-'+
CAST(dayCal as VARCHAR(2))+'-'+
CAST(yearCal as VARCHAR(4))
AS DATETIME
)
) IN(1,7)