A faster SQL Query to get this done - sql-server-2008

Question

I have a SP and UDF that brings me Totals. But I know there is a COUNT CASE WHEN query possible to get totals in a single go. Can anyone help me in this regard? My current query is just a redundant pause.
ALTER PROCEDURE [dbo].[GetMailBasketsForLocums]
AS
BEGIN
SET NOCOUNT ON;
SET FMTONLY OFF;
SET DATEFORMAT DMY;
SELECT DISTINCT Locum.OID,
Locum.FirstName + ' ' + Locum.LastName AS Name,
dbo.GetMailBasketTotalsForLocums(MailBasket.LocumId, 1) AS BookingsConfirmed,
dbo.GetMailBasketTotalsForLocums(MailBasket.LocumId, 3) AS BookingsCancelled,
dbo.GetMailBasketTotalsForLocums(MailBasket.LocumId, 5) AS BookingsSwitched,
(dbo.GetMailBasketTotalsForLocums(MailBasket.LocumId, 1) +
dbo.GetMailBasketTotalsForLocums(MailBasket.LocumId, 3) +
dbo.GetMailBasketTotalsForLocums(MailBasket.LocumId, 5)) AS Total
FROM MailBasket INNER JOIN
Locum
ON Locum.OID = MailBasket.LocumID
WHERE MailBasket.IsSent = 0
AND MailBasket.MailTypeID IN (1, 3, 5);
END
And
ALTER FUNCTION [dbo].[GetMailBasketTotalsForLocums]
(
#LocumID BIGINT,
#MailTypeID INT
)
RETURNS int
AS
BEGIN
DECLARE #Result int
SELECT #Result = COUNT(MailBasket.OID)
FROM MailBasket
WHERE MailBasket.MailTypeID = #MailTypeID
AND MailBasket.LocumID = #LocumID
AND MailBasket.IsSent = 0;
RETURN #Result
END
Regards.

Answer 1

SELECT
DISTINCT Locum.OID,
Locum.FirstName + ' ' + Locum.LastName AS Name,
COUNT(CASE WHEN MailBasket.MailTypeID = 1 THEN 1 ELSE NULL END) AS BookingsConfirmed,
COUNT(CASE WHEN MailBasket.MailTypeID = 3 THEN 1 ELSE NULL END) AS BookingsCancelled,
COUNT(CASE WHEN MailBasket.MailTypeID = 5 THEN 1 ELSE NULL END) AS BookingsSwitched,
COUNT(*) AS Total
FROM
MailBasket INNER JOIN
Locum
ON Locum.OID = MailBasket.LocumID
WHERE MailBasket.IsSent = 0
AND MailBasket.MailTypeID IN (1, 3, 5);
COUNT ignores NULLs to the conditional count works
You can also use SUM
SUM(CASE WHEN MailBasket.MailTypeID = 5 THEN 1 ELSE 0 END)

Answer 2

Try this:
SELECT DISTINCT Locum.OID, Locum.FirstName + ' ' + Locum.LastName AS Name,
COUNT(CASE WHEN MailBasket.MailTypeID = 1 THEN MailBasket.MailTypeID END) as BookingsConfirmed,
COUNT(CASE WHEN MailBasket.MailTypeID = 3 THEN MailBasket.MailTypeID END) as BookingsCancelled,
COUNT(CASE WHEN MailBasket.MailTypeID = 5 THEN MailBasket.MailTypeID END) as BookingsSwitched,
COUNT(*) as TOTAL
FROM MailBasket INNER JOIN
Locum
ON Locum.OID = MailBasket.LocumID
WHERE MailBasket.IsSent = 0
AND MailBasket.MailTypeID IN (1, 3, 5);

Answer 3

You can use a case inside a sum and group on the Locum records:
select
Locum.OID,
Locum.FirstName + ' ' + Locum.LastName AS Name,
sum(case when MailBasket.MailTypeID = 1 then 1 else 0 end) as BookingsConfirmed,
sum(case when MailBasket.MailTypeID = 3 then 1 else 0 end) as BookingsCancelled,
sum(case when MailBasket.MailTypeId = 5 then 1 else 0 end) as BookingsSwitched,
count(*) as Total
from
MailBasket
inner join Locum on Locum.OID = MailBasket.LocumID
where
MailBasket.IsSent = 0
and MailBasket.MailTypeID IN (1, 3, 5)
group by
Locum.OID, Locum.FirstName, Locum.LastName