从视图计算计数 (SQL)

Question

我有这个观点：

SELECT [ID]
      ,[PersonName]
      ,[PersonFUNCTION]
      ,[GUESTName]
      ,[Team]
      ,[sector]
      ,[MeetingCity]
      ,[GUESTCOMPANY]
      ,[TypeMeeting]
  FROM [DB_TEST].[dbo].[Meetings]

从这个观点我们可以阅读示例：

名称为“XXX”的人 (PersonName) 是首席执行官 (PersonFUNCTION)，他在巴黎 (MeetingCity) 与“Mark Zuckerberg” (GUESTName) 会面，“Facebook”是 (GUESTCOMPANY)，最后是会议是“一对一会议”（TypeMeeting）！

PS：请注意，XXX 可以多次与马克·扎克伯格会面，例如在不同的城市。

我想做的是：

添加 3 列：计数（一对一会议）和计数（一对一会议）和计数（小组会议）

• 计数（一对一会议）= [PersonName] 在一对一会议中与 [GUESTName] 会面的次数，无论城市不同或其他任何不同...

类似的东西：

SELECT [ID]
      ,[PersonName]
      ,[PersonFUNCTION]

     ,Count( One to One Meeting between PersonName and GUESTName )  ?
     ,Count( One to Few Meeting between PersonName and GUESTName)  ?
     ,Count ( Group Meeting between PersonName and GUESTName) ?

      ,[GUESTName]
      ,[Team]
      ,[sector]
      ,[MeetingCity]
      ,[GUESTCOMPANY]
      ,[TypeMeeting]
  FROM [DB_TEST].[dbo].[Meetings]

谢谢

Answer 1

这样的东西应该可以帮助您获取所有列和计数。

SELECT  [ID],
        [PersonName],
        [PersonFUNCTION],
        m2.OneToOneCount, --Count( One to One Meeting between PersonName and GUESTName )
        m2.OneToFewCount, --Count( One to Few Meeting between PersonName and GUESTName)
        m2.GroupCount,    --Count ( Group Meeting between PersonName and GUESTName) 
        [GUESTName],
        [Team],
        [sector],
        [MeetingCity],
        [GUESTCOMPANY],
        [TypeMeeting]
FROM    [DB_TEST].[dbo].[Meetings] m
        CROSS APPLY (SELECT COUNT(CASE WHEN m2.[TypeMeeting] = 'OneToOne' THEN 1 END) AS OneToOneCount,
                            COUNT(CASE WHEN m2.[TypeMeeting] = 'OneToFew' THEN 1 END) AS OneToFewCount,
                            COUNT(CASE WHEN m2.[TypeMeeting] = 'Group' THEN 1 END) AS GroupCount
                     FROM   [DB_TEST].[dbo].[Meetings] m2
                     WHERE  m2.[PersonName] = m.[PersonName]
                            AND m2.[GUESTName] = m.[GUESTName]) m2

如果您不能使用 CROSS APPLY，这是一个 JOIN 替代方案。

SELECT  [ID],
        [PersonName],
        [PersonFUNCTION],
        m2.OneToOneCount, --Count( One to One Meeting between PersonName and GUESTName )
        m2.OneToFewCount, --Count( One to Few Meeting between PersonName and GUESTName)
        m2.GroupCount,    --Count ( Group Meeting between PersonName and GUESTName) 
        [GUESTName],
        [Team],
        [sector],
        [MeetingCity],
        [GUESTCOMPANY],
        [TypeMeeting]
FROM    [DB_TEST].[dbo].[Meetings] m
        JOIN (  SELECT  [PersonName],
                        [GUESTName],
                        COUNT(CASE WHEN m2.[TypeMeeting] = 'OneToOne' THEN 1 END) AS OneToOneCount,
                        COUNT(CASE WHEN m2.[TypeMeeting] = 'OneToFew' THEN 1 END) AS OneToFewCount,
                        COUNT(CASE WHEN m2.[TypeMeeting] = 'Group' THEN 1 END) AS GroupCount
                FROM    [DB_TEST].[dbo].[Meetings] m2
                GROUP BY [PersonName],
                        [GUESTName]
         ) m2 ON m2.[PersonName] = m.[PersonName]
             AND m2.[GUESTName] = m.[GUESTName]

Answer 2

BM

另一种解决方案可能是使用SQL Pivot query

这里是示例数据和 SQL pivot Select 语句

SELECT *
FROM (
  SELECT
    [ID],
    [PersonName],
    [TypeMeeting]
  FROM [Meetings]
) TableData
PIVOT (
  Count(ID)
  FOR [TypeMeeting] IN (
    [T1],[T2],[T3],[T4],[T5],[T6]
  )
) PivotTable

我只是用'T1'等作为会议类型，您需要将它们替换为“[]”中的实际值

这是结果

如果你有很多不同的会议类型，你可以使用dynamic pivot query in SQL Server，但我想上面的解决方案就足够了

Answer 3

您可以使用条件聚合：

select PersonName, GuestName,
       sum(case when TypeMetting = 'one-to-one' then 1 else 0 end) as Num_OneToOne,
       sum(case when TypeMetting = 'one-to-few' then 1 else 0 end) as Num_OneToFew,
       sum(case when TypeMetting = 'group' then 1 else 0 end) as Num_Group
from Meetings
group by PersonName, GuestName;

Answer 4

你可以使用SQL COUNT function with Partition By子句

试试

SELECT Distinct [ID]
      ,[PersonName]
      ,[TypeMeeting] --...
      ,COUNT([TypeMeeting]) OVER (PARTITION BY [PersonName], [TypeMeeting]) Cnt
FROM [Meetings]

结果如下