之前的狀態，並根據ID和日期

Question

每個病人就診次數我對客戶的預約歷史以下細節：

**CustomerID Date Status** 
123  1/3/2017 Arrived 
123  1/9/2017 Not Arrived 
123  2/1/2017 Canceled 
123  2/25/2017 Arrived 
234  10/8/2016 Arrived 
234  11/3/2016 Not Arrived 
234  1/8/2017 Not Arrived 
234  1/8/2017 Not Arrived 
234  1/18/2017 Canceled 

我將如何使用SQL，計算每次遇到每個約會狀態的總和（已到達，取消，並沒有到達）不包括目前的遭遇？另外，我如何弄清楚每個客戶的預約狀態是什麼？ Linked是我試圖製作的屏幕截圖。先謝謝您的幫助！

Answer 1

下面的查詢：

SELECT appointment.[CustomerID] 
     ,appointment.[Date] 
     ,appointment.[Status] 
     ,(SELECT COUNT(*) FROM [CustomerAppointment] as arrived 
     WHERE arrived.CustomerID = appointment.CustomerID 
     AND arrived.Date < appointment.Date 
     AND arrived.Status = 'Arrived') as [ArrivedSum] 
     ,(SELECT COUNT(*) FROM [CustomerAppointment] as arrived 
     WHERE arrived.CustomerID = appointment.CustomerID 
     AND arrived.Date < appointment.Date 
     AND arrived.Status = 'Canceled') as [CanceledSum] 
     ,(SELECT COUNT(*) FROM [CustomerAppointment] as arrived 
     WHERE arrived.CustomerID = appointment.CustomerID 
     AND arrived.Date < appointment.Date 
     AND arrived.Status = 'Not Arrived') as [NotArrivedSum] 
     ,(SELECT COUNT(*) FROM [CustomerAppointment] as arrived 
     WHERE arrived.CustomerID = appointment.CustomerID 
     AND arrived.Date < appointment.Date) as [TotalAppointments] 
     ,CASE WHEN (SELECT COUNT(*) FROM [CustomerAppointment] as arrived 
     WHERE arrived.CustomerID = appointment.CustomerID 
     AND arrived.Date < appointment.Date) = 0 THEN 'First' ELSE appointment.[Status] END as [LastApptStatus] 
    FROM [dbo].[CustomerAppointment] as appointment 
    GROUP BY appointment.[CustomerID],appointment.[Date],appointment.[Status] 

會給你你正在等待結果。

另外，我建議你使用技術主鍵，以避免從計算中忘記相同的客戶ID /日期的條目。一個簡單的IDENTITY將會很好。

隨着PK的查詢會是這樣：

SELECT appointment.[CustomerID] 
     ,appointment.[Date] 
     ,appointment.[Status] 
     ,(SELECT COUNT(*) FROM [CustomerAppointment] as arrived 
     WHERE arrived.CustomerID = appointment.CustomerID 
     AND arrived.myPK < appointment.myPK 
     AND arrived.Status = 'Arrived') as [ArrivedSum] 
     ,(SELECT COUNT(*) FROM [CustomerAppointment] as arrived 
     WHERE arrived.CustomerID = appointment.CustomerID 
     AND arrived.myPK < appointment.myPK 
     AND arrived.Status = 'Canceled') as [CanceledSum] 
     ,(SELECT COUNT(*) FROM [CustomerAppointment] as arrived 
     WHERE arrived.CustomerID = appointment.CustomerID 
     AND arrived.myPK < appointment.myPK 
     AND arrived.Status = 'Not Arrived') as [NotArrivedSum] 
     ,(SELECT COUNT(*) FROM [CustomerAppointment] as arrived 
     WHERE arrived.CustomerID = appointment.CustomerID 
     AND arrived.myPK < appointment.myPK) as [TotalAppointments] 
     ,CASE WHEN (SELECT COUNT(*) FROM [CustomerAppointment] as arrived 
     WHERE arrived.CustomerID = appointment.CustomerID 
     AND arrived.myPK < appointment.myPK) = 0 THEN 'First' ELSE appointment.[Status] END as [LastApptStatus] 
    FROM [dbo].[CustomerAppointment] as appointment 
    GROUP BY appointment.[CustomerID],appointment.[Date],appointment.[Status]