SQL GROUP BY Aggregate

Question

票證有一個ID，TicketNbr和Time Entries有一個ID Time_RecID。票證有0,1或可能更多與TicketNbr相關的時間條目。

我想產生像這樣的列表：

Time Entries | Tickets 
      10 | # 
      9 | # 
      8 | # 
      7 | # 
      6 | # 
      5 | # 
      4 | # 
      3 | # 
      2 | # 
      1 | # 

凡＃的門票數量。

數據來自兩個表：v_rpt_Service（TicketNbr）和v_rpt_Time（Time_RecID）。我所有的相關數據都是使用下面的SQL發現的：

SELECT 
    s.TicketNbr, t.Time_RecID 
FROM 
    v_rpt_Service s 
    LEFT JOIN v_rpt_time t on s.TicketNbr = t.SR_Service_RecID 

我在哪裏掙扎的是聚合。理想情況下，我正在尋找的是：

SELECT 
    COUNT(T.Time_recID) as Time_Entries, COUNT(DISTINCT(s.TicketNbr)) as Tickets 
FROM 
    v_rpt_Service s 
    LEFT JOIN v_rpt_time t on s.TicketNbr = t.SR_Service_RecID 
GROUP BY 
    COUNT(t.Time_recID) 

導致這個錯誤：

Msg 144, Level 15, State 1, Line 8 Cannot use an aggregate or a subquery in an expression used for the group by list of a GROUP BY clause.

如何重構初始查詢給我像輸出上面的列表？

Answer 1

SELECT q.TimeEntries,count(q.TicketNbr) As Tickets 
FROM (SELECT 
      s.TicketNbr, count(t.Time_RecID) As TimeEntries 
     FROM 
      v_rpt_Service s 
     LEFT JOIN v_rpt_time t on s.TicketNbr = t.Time_RecID 
     GROUP BY s.TicketNbr) As q 
GROUP BY q.TimeEntries 
ORDER BY q.TimeEntries DESC 

您可能需要考慮當車票已經沒有時間條目（我假設可能是考慮到LEFT JOIN

Answer 2

您可以嵌套查詢的情況下，會發生什麼：

SELECT TicketNbr, count(Time_RecID) 
FROM 
(SELECT 
    s.TicketNbr, t.Time_RecID 
FROM 
    v_rpt_Service s 
    LEFT JOIN v_rpt_time t on s.TicketNbr = t.Time_RecID) AS table 
GROUP BY 
Time_RecID