declare @str1 varchar(max); declare @count int; set @count = 0; print 'begin' while @count < 10000000 begin set @str1 = @str1 + '*'; set @count = @count +1; end print @str1 print 'end' --time usage:00:01:17 declare @str1 nvarchar(max); declare @count int; set @count = 0; print 'begin' while @count < 10000000 begin set @str1 = @str1 + '*'; set @count = @count +1; end print @str1 print 'end' --time usage:00:01:17 --conclusion the same