如何在STUFF函数（XML路径）中包含字符串文本？

Code:

码：

ISNULL(LTRIM(STUFF( (SELECT ', ' + PL.Pipe_Product
                            FROM Reporting.PipelineInformation PL
                            WHERE PL.Project_ID = TI.Project_ID 
                            FOR XML PATH('')), 1, 1, '')),'___________') AS Pipe_Product
ISNULL(LTRIM(STUFF( (SELECT ', '