Number of entries per month - sql

Question

I have something similar to the following situation, probably not the best example but somewhat similar to what I really have. Let's say I have 4 tables that due to certain circumstances I can't change.
CREATE TABLE [Hospital] (
[HospitalID] INT IDENTITY NOT NULL,
[HospitalName] VARCHAR(MAX) NOT NULL
);
CREATE TABLE [Doctors] (
[DoctorID] INT IDENTITY NOT NULL ,
[HospitalID] INT NOT NULL,
[DoctorName] VARCHAR(MAX) NOT NULL
);
CREATE TABLE [Patient] (
[PatientID] INT IDENTITY NOT NULL ,
[DoctorID] INT NOT NULL
);
CREATE TABLE [PatientAppointment] (
[PatientID] INT IDENTITY NOT NULL,
[Date] DATETIME NOT NULL
);
I want to write a stored procedure that get's a year and a month as parameters and it is supposed to return [HospitalName] , [DoctorsName] and the number of patient appointments for that time period.
This is what I have now and I am stuck
CREATE PROCEDURE [dbo].[Procedure]
#year INT ,
#month INT
AS
SELECT COUNT([Date]) AS NumberOfAppointments FROM [PatientAppointment]
WHERE MONTH([Date]) = #month AND YEAR([Date]) = #year
SELECT [Hospital].HospitalName , [Doctors].DoctorName FROM [Doctors]
INNER JOIN [Hospital] ON [Hospital].HospitalID = [Doctors].DoctorID
RETURN 0
I can't figure out how to extract the info I need and I am limited to one stored procedure.

Answer 1

try this:
CREATE PROCEDURE [dbo].[Procedure]
#year INT ,
#month INT
AS
BEGIN
SELECT h.HospitalId, d.DoctorName, count(p.PatientId) as NumberOfAppointments
FROM Hospital h
INNER JOIN Doctors d
ON h.HospitalId = d.HospitalId
INNER JOIN Patient p
ON d.DoctorId = p.DoctorId
INNER JOIN PatientAppointment ap
ON p.PatientId = ap.PatientId
AND MONTH(ap.[Date]) = #month
AND YEAR(ap.[Date]) = #year
GROUP BY h.HospitalId, d.DoctorName
END

Answer 2

My answer is very similar to the one posted by Joachim but there is one VERY significant difference. This code is SARGable where the original query and the fine example already posted are not. Since you say you can't change the table structure I will refrain from suggesting changes....although you could greatly improve on these structures.
Create Procedure dbo.SomeBetterName
(
#Date date
) AS
select h.HospitalName
, d.DoctorName
, COUNT(pa.[Date]) as NumAppointments
from Hospital h
join Doctors d on h.HospitalID = d.HospitalID
join Patient p on p.DoctorID = d.DoctorID
join PatientAppointment pa on pa.PatientID = p.PatientID
where pa.Date >= dateadd(month, datediff(month, 0, #Date), 0)
and pa.Date < dateadd(month, datediff(month, 0, #Date) + 1, 0)
group by h.HospitalName
, d.DoctorName