How to use IF statement in SQL Server 2005? - sql

Question

This is the scenario I would like to have in my INSERT in a stored procedure.
Tables:
tblRate
RateID (pk)
Rate money
Days int
isDailyRate bit
tblBooking
Totals money
In my vb app this is the statement. How would I translate this into T-SQL?
if !isDaily = True then
!Totals = (!Days * !Rate)
else
!Totals = !Rate
end if
This is my stored procedure:
Create PROCEDURE [dbo].[sp_tblBooking_Add]
(
#RateID bigint,
#Rate money,
#Days int,
#CheckOUT datetime
)
AS
BEGIN
--Below is the logic I want. I can't get the right syntax
--Declare #myTotals as money
--Declare #myCheckOut as DateTime
--if (Select isDailyRate FROM tblRates WHERE (RateID = #RateID)) = True THEN
-- set myTotals = (#Rate * #Days)
-- set #CheckOUT = DATEADD(DAY, DATEDIFF(DAY, 0, GETDATE()) + #Days, '12:00')
--Else
-- set myTotals = #Rate
-- set #CheckOUT = GETDATE()
--End if
INSERT INTO tblBooking(Totals, CheckOUT)
VALUES(#myTotals, #myCheckOut);
END

Answer 1

Use the CASE expression:
INSERT INTO tblBooking (Totals, CheckOUT)
SELECT
CASE
WHEN idDailyRate = 1 THEN #Rate * #Days
ELSE #rate
END,
CASE
WHEN idDailyRate = 1 THEN DATEADD(DAY,
DATEDIFF(DAY, 0, GETDATE()) + #Days,
'12:00')
ELSE GETDATE()
END
FROM tblRates
WHERE RateID = #RateID;
Or, if they are scalar values, then you can select them into a variables and insert them instead of INSERT ... INTO ... SELECT.
Update 1
Like this:
Declare #myTotals as money;
Declare #myCheckOut as DateTime;
SELECT
#myTotals = CASE
WHEN idDailyRate = 1 THEN #Rate * #Days
ELSE #rate
END,
#myCheckOut = CASE
WHEN idDailyRate = 1 THEN DATEADD(DAY,
DATEDIFF(DAY, 0, GETDATE()) + #Days,
'12:00')
ELSE GETDATE()
END
FROM tblRates
WHERE RateID = #RateID;
INSERT INTO tblBooking (Totals, CheckOUT) VALUES(#myTotals, #myCheckOut );
But this will give you an error, if there is more than value returned from this table tblRates into those variables.