sql server存儲過程獲取參加活動的人數

Question

我需要顯示回答yes參加活動的人數。這裏是我的SELECT語句至今：

SELECT TOP (100) PERCENT 
    dbo.tb_EventAttendance.WillAttend, 
    dbo.tb_Events.EventName, 
    dbo.tb_Events.EventDate 
FROM dbo.tb_EventAttendance 
INNER JOIN dbo.tb_Events ON dbo.tb_EventAttendance.EventID = dbo.tb_Events.dbID 
WHERE (dbo.tb_EventAttendance.WillAttend = 'Y') 
ORDER BY dbo.tb_Events.EventDate 

難道我使用COUNT函數，如果是在究竟這種情況呢？

Answer 1

您需要同時使用COUNT和GROUP BY（因爲總COUNT）：

SELECT TOP (100) PERCENT dbo.tb_Events.EventName, dbo.tb_Events.EventDate, 
COUNT(dbo.tb_EventAttendance.WillAttend) as NumAttendees, 
FROM dbo.tb_EventAttendance INNER JOIN 
dbo.tb_Events ON dbo.tb_EventAttendance.EventID = dbo.tb_Events.dbID 
WHERE  (dbo.tb_EventAttendance.WillAttend = 'Y') 
GROUP BY dbo.tb_EventName, dbo.tb_Events.EventDate 
ORDER BY dbo.tb_Events.EventDate