Unstable query in SQL Server

Question

I am using SQL Server 2008-R2 Express Edition.

I wrote the query shown below to generate number sequences from 1 to @n. In testing it (purely in a query window), I found that if I significantly change the value of @n, I get incorrect results. Re-execution yields the same errors. However, if I open a new query window, the results are perfect.

Looking at the algorithm, it makes no sense to me as to why I should be getting unstable results (or even that a query can produce varying results against a fixed input).

DECLARE @n INT;

SET @n = 65536;

DECLARE @t TABLE (n INT NOT NULL PRIMARY KEY);

IF @n > 0 BEGIN
    DECLARE @r INT, @i INT, @l INT;

    SET @r = FLOOR(1.442695040888964 * LOG(@n));
    SET @i = 1;
    SET @l = 0;

    INSERT INTO @t (n) VALUES (1);

    WHILE @l < @r BEGIN
        INSERT INTO @t (n) SELECT n + @i FROM @t;

        SET @i = @i * 2;
        SET @l = @l + 1;
    END;

    INSERT INTO @t (n) SELECT TOP (@n - @i) n + @i FROM @t;
END;

--SELECT COUNT(1) FROM @t;

select * from @t

EDIT

Change the 65536 to 5000, execute, change back to 65536, and scroll down to say row 169,770. I get row 169770 = 40000. In a new window, it runs correctly.

EDIT2

Besides getting randomly correct/incorrect results, it appears something else is wrong. I now am getting consistently incorrect results for some numbers such as 655360.

Answer 1

Add an ORDER BY to the last statement.

There is no natural or default order in any table

Edit:

I attribute it the use of floating point numbers

I posted how to do a tally table an hour ago: Maximum recursion has been exhausted