I got it to work by doing this:

declare @sql nvarchar (max)

declare @server varchar(64)

declare @db varchar(64)

declare @table varchar(64)

select @server = quotename(parsename('[server].j3688802s.dbo.sample_web', 4))

select @db = parsename('[server].j3688802s.dbo.sample_web', 3)

select @table = parsename('[server].j3688802s.dbo.sample_web', 1)

print (@server)

print (@db)

print (@table)

set @sql = 'Select Stuff((SELECT '', '' + quotename(column_name) AS [text()]

FROM

(SELECT column_name FROM ' + @server + '.' + @db + '.information_schema.columns

where table_name = ''' + @table + '''

) x

For XML PATH ('''')),1,1,'''')'

print (@sql)

exec sp_executesql @sql, N'@sql nvarchar(max)', @sql print (@sql)

I've never used sp_executesql before. So, I'll experiment with FOR XML, until I run into it truncating column lists.

Thanks guys!