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