You are the administrator of a SQL Server 2000 computer at a doctor's
office. The server contains a database named Medical. The database stores
patient and treatment information and is configured as shown in the
exhibit.

The office accountant needs access to the total number of treatments that
have been performed in the office. The accountant should not have access
to any other patient data and should not be able to change any information
in the database.

The accountnat has a SQL Server Authenticated login and database user
account named AccountUser.

You need to make the appropriate information available to the accountant,
while protecting the other information in the database. Which batch of
Transact-SQL statements should you execute?

A. CREATE VIEW TotalTreatments AS SELECT COUNT(PatientID) AS Total FROM dbo.Patients GO GRANT ALL ON TotalTreatments TO AccountUser
B. CREATE VIEW TotalTreatments AS SELECT COUNT(*) AS Total FROM dbo.Patients GO GRANT ALL ON TotalTreatments TO AccountUser
C. CREATE PROCEDURE TotalTreatments AS SELECT COUNT(*) AS Total FROM dbo.Patients GO GRANT ALL ON TotalTreatments TO AccountUser
D. CREATE PROCEDURE TotalTreatments AS SELECT COUNT(PatientID) AS Total FROM dbo.Patients GO GRANT ALL ON TotalTreatments TO AccountUser

Testking предлагает следующий ответ С
с объяснением

Using a procedure is a good way of protecting from direct access to the user table. The users would only have to be granted acces to the procedure not to the underlined table.
(Хотя в данном случае VIEW not updatable, и мое субьективное мнение, что пользователям из VIEW легче получить данные, чем из PROCEDURE )

We must use COUNT(*) since COUNT(*) returns the number of rows that math the search conditions specified in the query without eliminated duplicates. It counts each row separately, including rows that contain null values.
COUNT(PatientID) would count distinct rows and would not include rows with NULL values in the PatientID column
(Хотя в данном случае PatientID PRIMARY KEY Он не может содержать NULL и неуникальные значения. Следовательно COUNT(PatientID) =COUNT(*) и даже предпочтительнее, так как теоретически выполняется быстрее)

НО самое главное, в вопросе требуется посчитать общее количество посещений, которое надо считать по таблице посещений Treatments, а не по таблице пациентов Patients
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