将 SQL 字符串别名组合成逗号分隔的字符串答案

【问题标题】：Combining SQL string alias into comma delimited string将 SQL 字符串别名组合成逗号分隔的字符串
【发布时间】：2018-01-19 23:59:41
【问题描述】：

我正在处理这个存储过程，它检查哪些 BIT 字段是真实的，并根据它使用别名为其分配一个文本。我希望能够组合这些别名值（字符串）并将其以逗号分隔，以便我可以将其显示在我的 SSRS 报告中。下面是我存储过程的一部分。

 ,CASE
  WHEN sr.[ReservationAlreadySentAttached] = 1 THEN 'Reservation Already Sent'
  END                           AS ReservationAttached

  ,CASE
  WHEN sr.[HPOfficeAttached] = 1 THEN 'H&P Office'
  END                           AS HPOfficeAttached

  WHEN sr.[NotesAttached] = 1 THEN 'Notes'
  END                           AS NotesAttached

  ,CASE
  WHEN sr.[OpPermitAttached] = 1 THEN 'Op Permit'
  END                           AS OpPermitAttached

  ,CASE
  WHEN sr.[TestResultsAttached] = 1 THEN 'Test Results'
  END                           AS TestResultsAttached

  ,CASE
  WHEN sr.[ConsultationReportsAttached] = 1 THEN 'Consultation Reports'
  END                           AS ConsultationReportsAttached

  ,CASE
  WHEN sr.[OtherAttached] = 1 THEN 'Other'
  END                           AS OtherAttached

因此，如果只有 NotesAttached 和 ReservationAlreadySentAttached 是真实的，那么我希望最终结果显示为 Notes，Reservation Already Sent。我如何连接这些别名？

【问题讨论】：

标签： sql sql-server-2008 stored-procedures reporting-services concatenation

【解决方案1】：

另一种选择是构建您的字符串，然后使用 STUFF() 删除前导逗号

示例（缩写）

Declare @YourTable table (ReservationAlreadySentAttached bit,HPOfficeAttached bit,NotesAttached bit)
Insert Into @YourTable values
(1,0,1)

Select NewValue = stuff(
                   case when ReservationAlreadySentAttached = 1 then ', Reservation Already Sent' else '' end
                  +case when HPOfficeAttached               = 1 then ', H&P Office'               else '' end
                  +case when NotesAttached                  = 1 then ', Notes'                    else '' end
                  ,1,2,'')
 From  @YourTable

退货

NewValue
Reservation Already Sent, Notes

编辑 - 只是表达

 NewValue = stuff(
                   case when sr.[ReservationAlreadySentAttached] = 1 then ', Reservation Already Sent' else '' end
                  +case when sr.[HPOfficeAttached]               = 1 then ', H&P Office'               else '' end
                  +case when sr.[NotesAttached]                  = 1 then ', Notes'                    else '' end
                  ,1,2,'')

【讨论】：

我被你的回答卡住了@John Cappelletti。为什么我需要声明一个表？我只是想要一个与我的别名连接的字符串
@HereToLearn_ (at)YourTable 只是一个用于演示/说明的表变量。删除 SELECT 上面的所有内容（前 3 行）并将 (at)YourTable 更改为您的表名
@HereToLearn_ 用“只是表达”更新了答案
好酷。感谢您的快速回复！ 1,2 是什么意思？我打算在括号内再添加 4 个案例。我还需要更新什么吗？
@HereToLearn_ Stuff() 将从位置 1 开始的字符替换为 2 个空格的 ''... 从而消除前导 ,{space}

【解决方案2】：

CASE
  WHEN sr.[ReservationAlreadySentAttached] = 1 THEN ', Reservation Already Sent' ELSE ''
  END  
+ CASE
  WHEN sr.[HPOfficeAttached] = 1 THEN ', H&P Office' ELSE ''
  END                        
+ CASE etc...

并将其包装在某个函数中以删除第一个逗号 + 空格。

【讨论】：

如果没有 ELSE，您将面临连接 NULL 的风险
问题@TabAlleman。我在哪里定义将具有最终串联字符串列表的变量字符串？
如果你想填充一个变量，那么你可以把它放在列定义之前，比如@MyVariable=STUFF(CASE WHEN...

【解决方案3】：

不是最漂亮的解决方案...

RIGHT((CASE 
        WHEN sr.[ReservationAlreadySentAttached] = 1
            THEN ',Reservation Already Sent'
        END + CASE 
        WHEN sr.[HPOfficeAttached] = 1
            THEN ',H&P Office'
        END + CASE 
        WHEN sr.[NotesAttached] = 1
            THEN ',Notes'
        END + CASE 
        WHEN sr.[OpPermitAttached] = 1
            THEN ',Op Permit'
        END + CASE 
        WHEN sr.[TestResultsAttached] = 1
            THEN ',Test Results'
        END + CASE 
        WHEN sr.[ConsultationReportsAttached] = 1
            THEN ',Consultation Reports'
        END + CASE 
        WHEN sr.[OtherAttached] = 1
            THEN ',Other'
        END)
,LEN(CASE 
        WHEN sr.[ReservationAlreadySentAttached] = 1
            THEN ',Reservation Already Sent'
        END + CASE 
        WHEN sr.[HPOfficeAttached] = 1
            THEN ',H&P Office'
        END + CASE 
        WHEN sr.[NotesAttached] = 1
            THEN ',Notes'
        END + CASE 
        WHEN sr.[OpPermitAttached] = 1
            THEN ',Op Permit'
        END + CASE 
        WHEN sr.[TestResultsAttached] = 1
            THEN ',Test Results'
        END + CASE 
        WHEN sr.[ConsultationReportsAttached] = 1
            THEN ',Consultation Reports'
        END + CASE 
        WHEN sr.[OtherAttached] = 1
            THEN ',Other'
        END) - 1 )

编辑：当 NONE 为 1 时，您可能必须考虑到，这样您就不会得到 Invalid length parameter passed to the right function.

【讨论】：