Question

我需要将多行的列结果合并为一个变量。我的数据集样本可以在下面找到。

EmailAddress
-------------
myemail@here.com
youremail@here.com

目前，我正在使用STUFF将EmailAddress列合并为分号分隔列表。下面是一个样本。

SELECT @EmailAddress = CONVERT(nvarchar(max)    
              , STUFF(
                  (SELECT ';' + EmailAddress FROM EmployeeCourseDetails)
                , 1
                , 1
                , '')
              )

期望的结果应该看起来像myemail@here.com;youremail@here.com但是当我执行语句时，我收到以下错误：Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression.

请帮忙吗？

Answer 1

您可以使用COALESCE：

DECLARE @EmailAddress VARCHAR(8000) 

SELECT   @EmailAddress = COALESCE(@EmailAddress + ';', '') + EmailAddress
FROM     EmployeeCourseDetails
ORDER BY EmailAddress

SELECT @EmailAddress

DEMO

结果：myemail@here.com;youremail@here.com

Answer 2

我用FOR XML PATH('')做过类似的事情。像这样：

SELECT @EmailAddress = CONVERT(nvarchar(max)    
              , STUFF(
                  (SELECT ';' + EmailAddress FROM EmployeeCourseDetails FOR XML PATH(''))
                , 1
                , 1
                , '')
              )

将多行的列值合并为1

2 个答案: