T-SQL MS SQL 的东西。如何使用group by将行组合成单行答案

【问题标题】：T-SQL MS SQL Stuff. How to combine rows into single row with group byT-SQL MS SQL 的东西。如何使用group by将行组合成单行
【发布时间】：2021-01-14 03:01:59
【问题描述】：

我有一个 SQL 查询：

SELECT [B].[Id]
      ,[B].[CreateDate]
      ,[Author]
      ,[B].[WorkcenterId]
      ,[B].[AreaId]
      ,[B].[SubAreaId]
      ,[B].[Description]
      ,[PriorityId]
      ,[BreakdownStatusEnum]
      ,[ApproveDate]
      ,[StartDate]
      ,[FinishedDate]
      ,[BreakdownStartCheckListId]
      ,[ApprovedBy]
      ,[BreakdownReason]
      ,[D].[Name] AS ResponsibleDepartment
  FROM [Breakdowns_Kohl].[dbo].[Breakdowns] AS [B]
  INNER JOIN Workcenters AS [WC] ON B.WorkcenterId = WC.Id
  INNER JOIN SubAreas AS [S] ON B.SubAreaId = S.Id
  INNER JOIN Areas AS [A] ON B.AreaId = A.ID
  LEFT JOIN Relation_Department_Workcenter AS REL_DW ON B.WorkcenterId = REL_DW.WorkcenterId
  LEFT JOIN Department AS [D] ON REL_DW.DepartmentId = D.Id

返回表：

我不知道如何将它放入最后一列并用逗号分隔的单行中，例如：

【问题讨论】：

这能回答你的问题吗？ Simulating group_concat MySQL function in Microsoft SQL Server 2005?
按除此之外的所有内容进行分组。然后使用 STRING_AGG

标签： sql-server tsql string-aggregation stuff

【解决方案1】：

要将最后一列聚合成一个逗号分隔的字符串，名为 ResponsibleDepartment，类似这样

SELECT [B].[Id]
      ,[B].[CreateDate]
      ,[Author]
      ,[B].[WorkcenterId]
      ,[B].[AreaId]
      ,[B].[SubAreaId]
      ,[B].[Description]
      ,[PriorityId]
      ,[BreakdownStatusEnum]
      ,[ApproveDate]
      ,[StartDate]
      ,[FinishedDate]
      ,[BreakdownStartCheckListId]
      ,[ApprovedBy]
      ,[BreakdownReason]
      ,string_agg([D].[Name] , ',') within group (order by [B].id) ResponsibleDepartment
  FROM [Breakdowns_Kohl].[dbo].[Breakdowns] AS [B]
  INNER JOIN Workcenters AS [WC] ON B.WorkcenterId = WC.Id
  INNER JOIN SubAreas AS [S] ON B.SubAreaId = S.Id
  INNER JOIN Areas AS [A] ON B.AreaId = A.ID
  LEFT JOIN Relation_Department_Workcenter AS REL_DW ON B.WorkcenterId = REL_DW.WorkcenterId
  LEFT JOIN Department AS [D] ON REL_DW.DepartmentId = D.Id

group by [B].[Id],
      [B].[CreateDate]
      ,[Author]
      ,[B].[WorkcenterId]
      ,[B].[AreaId]
      ,[B].[SubAreaId]
      ,[B].[Description]
      ,[PriorityId]
      ,[BreakdownStatusEnum]
      ,[ApproveDate]
      ,[StartDate]
      ,[FinishedDate]
      ,[BreakdownStartCheckListId]
      ,[ApprovedBy]
      ,[BreakdownReason]

【讨论】：

【解决方案2】：

如果您使用的是 SQL Server 2017 或更高版本，您可以轻松使用 String_AGG 聚合函数，如果不是，您可以使用 stuff 函数和 xml，就像在这个问题中一样：

string_agg for sql server pre 2017

【讨论】：