Question

如果内容中只有一个值，我想在最后删除逗号，但是应该存在一个以上的值谢谢！

select
Names= (STUFF((
  SELECT ', ' +     CONCAT(
                CASE WHEN RegistryUser.FirstName IS NOT NULL AND RegistryUser.LastName IS NOT NULL THEN RegistryUser.FirstName ELSE App.FirstName END,
                ' ',
                CASE WHEN RegistryUser.FirstName IS NOT NULL AND RegistryUser.LastName IS NOT NULL THEN RegistryUser.LastName ELSE App.LastName END
            ) AS Names
    FROM ConsultingEventConsultant
            LEFT JOIN App
                ON ConsultingEventConsultant.AppID = App.AppID
            LEFT JOIN RegistryUser
                ON App.UserID = RegistryUser.UserID
            WHERE ConsultingEventConsultant.consultingeventid = 56428 
            and ConsultingEventConsultant.CECID != (SELECT TOP 1 CECID FROM ConsultingEventConsultant CEC WHERE CEC.ConsultingEventID = 56428 ORDER BY CECID)
              FOR XML PATH(''), TYPE).value('.', 'NVARCHAR(MAX)'
             ), 1, 1, ''))

John Doe

约翰·多伊（Sara Smith）

Answer 1

正如约翰·卡佩莱蒂（John Cappelleti）所述，您要删除前导逗号（尽管不是前导空格），并且如果有尾随逗号，则返回空白行。

要删除前导空格，只需将末尾的第二个1更改为2，如下所示。

select
Names= (STUFF((
  SELECT ', ' +     CONCAT(
                CASE WHEN RegistryUser.FirstName IS NOT NULL AND RegistryUser.LastName IS NOT NULL THEN RegistryUser.FirstName ELSE App.FirstName END,
                ' ',
                CASE WHEN RegistryUser.FirstName IS NOT NULL AND RegistryUser.LastName IS NOT NULL THEN RegistryUser.LastName ELSE App.LastName END
            ) AS Names
    FROM ConsultingEventConsultant
            LEFT JOIN App
                ON ConsultingEventConsultant.AppID = App.AppID
            LEFT JOIN RegistryUser
                ON App.UserID = RegistryUser.UserID
            WHERE ConsultingEventConsultant.consultingeventid = 56428 
            and ConsultingEventConsultant.CECID != (SELECT TOP 1 CECID FROM ConsultingEventConsultant CEC WHERE CEC.ConsultingEventID = 56428 ORDER BY CECID)
              FOR XML PATH(''), TYPE).value('.', 'NVARCHAR(MAX)'
             ), 1, 2, ''))

要查看有关空白行的更多信息，请运行以下命令。然后，您应该能够找到错误的数据并修复它或查询中的错误逻辑（以引起空白行的情况为准）。

SELECT ', ' +     CONCAT(
                CASE WHEN RegistryUser.FirstName IS NOT NULL AND RegistryUser.LastName IS NOT NULL THEN RegistryUser.FirstName ELSE App.FirstName END,
                ' ',
                CASE WHEN RegistryUser.FirstName IS NOT NULL AND RegistryUser.LastName IS NOT NULL THEN RegistryUser.LastName ELSE App.LastName END
            ) AS Names,
            *
    FROM ConsultingEventConsultant
            LEFT JOIN App
                ON ConsultingEventConsultant.AppID = App.AppID
            LEFT JOIN RegistryUser
                ON App.UserID = RegistryUser.UserID
            WHERE ConsultingEventConsultant.consultingeventid = 56428 
            and ConsultingEventConsultant.CECID != (SELECT TOP 1 CECID FROM ConsultingEventConsultant CEC WHERE CEC.ConsultingEventID = 56428 ORDER BY CECID)

Answer 2

我建议注意何时找不到名称。也许这满足您的需求：

        void ThreadMain()
        {
            process.BeginOutputReadLine();
            process.BeginErrorReadLine();

            while( true ) 
            { 
                // ...

                Thread.Sleep( 250 ); 
            } 

            process.CancelOutputRead();
            process.CancelErrorRead();

            Dispose();
        }

或者，您可能想要添加如下逻辑：

select STUFF((SELECT ', ' + 
                     COALESCE(ru.FirstName + ' ' + ru.LastName, 
                              a.FirstName + ' ' + a.LastName,
                              '<NO NAME FOUND>'
                             ) AS Names
              FROM ConsultingEventConsultant c3c LEFT JOIN
                   App a
                   ON cec.AppID = a.AppID LEFT JOIN
                   RegistryUser ru
                   ON a.UserID = ru.UserID
              WHERE cec.consultingeventid = 56428 AND
                    cec.CECID <> (SELECT TOP 1 cec2CECID
                                  FROM ConsultingEventConsultant CEC2 
                                  WHERE CEC2.ConsultingEventID = 56428                                 ORDER BY CECID
                                 )
              FOR XML PATH(''), TYPE).value('.', 'NVARCHAR(MAX)'
             ), 1, 2, ''
            ) as names

到(ru.FirstName IS NOT NULL OR a.FirstName IS NOT NULL) AND子句。

如果我只有一个值，请从STUFF中删除逗号

2 个答案: