Almost:

declare @server varchar(64)

declare @db varchar(64)

declare @table varchar(64)

declare @liststr nvarchar (max)

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)

exec ('select @liststr = coalesce(@liststr+'+''''+','+''''+' ,'+''''+''''+') + quotename(column_name)

from '+ @server + '.'+ @db+ '.information_schema.columns where table_name = '+ ''''+ @table+'''')

I was running in to this yesterday with a different set up, and couldn't figure out why.