使用 COALESCE 函数在变量中附加消息

下面是我的代码。

DECLARE @msg NVARCHAR(MAX) = NULL

;WITH CTE AS (
                    SELECT 'A' AS Message
                UNION
                    SELECT 'B' AS Message
                UNION
                    SELECT 'C' AS Message
                UNION
                    SELECT 'D' AS Message
)

SELECT @msg = COALESCE(ISNULL(@msg,'Attachements') + ', ','') +  Message FROM CTE

SELECT @msg + ' are missing.'

它正在生成输出：-

Attachments, A, B, C, D are missing.

如何避免单词后第一个逗号“Attachments“ ？ 请帮忙。

满足要求的其他技术也将受到欢迎。

Thanks.

而不是使用未记录/不受支持的字符串连接方式 https://sqlblog.org/2011/03/08/t-sql-tuesday-16-this-is-not-the-aggregate-youre-looking-for, use FOR XML PATH反而：

DECLARE @msg NVARCHAR(MAX) = NULL

;WITH CTE AS (
    SELECT 'A' AS Message
    UNION
    SELECT 'B' AS Message
    UNION
    SELECT 'C' AS Message
    UNION
    SELECT 'D' AS Message
)

SELECT @msg = 'Attachments ' + 
    STUFF((
        SELECT ', ' + Message 
        FROM CTE
        ORDER BY Message
        FOR XML PATH(''), TYPE).value('.[1]', 'NVARCHAR(MAX)')
    , 1, 2, ' ')

SELECT @msg + ' are missing.'