My biggest mistake was 10 years ago when I emailed an employee about 46,000 alerts due to an infinite loop.


-- infinite loop example
DECLARE @t table (tkey int not null);
INSERT into @t values (1),(2),(3);

DECLARE @i int;

SELECT @i = tkey FROM @t;

WHILE @i IS NOT NULL
BEGIN
    PRINT @i;

    DELETE FROM @t where tkey = @i;

    -- @i is not set if there are no rows in @t
    SELECT @i = tkey from @t;

    -- that was an infinite loop, should have used the following line instead
    -- SET @i = (SELECT TOP(1) tkey from @t);
END