How to select rows, and nearby rows

This is your existing logic rewritten using an moving max:

WITH dt AS (   SELECT      ID, AddedDate,      -- check if there's a NULL within a range of +/- 3 rows      -- and remember it's ID       max(case when AddedDate is null then id end)      over (order by id             rows between 3 preceding and 3 following) as NullID   FROM Items )SELECT *FROM dtwhere id between NullID-3 and NullID+3

Here is one method that uses the windowing clause:

select i.*from (select i.*,             count(*) over (order by id rows between 3 preceding and 1 preceding) as cnt_prec,             count(*) over (order by id rows between 1 following and 3 following) as cnt_foll,             count(addeddate) over (order by id rows between 3 preceding and 1 preceding) as cnt_ad_prec,             count(addeddate) over (order by id rows between 1 following and 3 following) as cnt_ad_foll      from items     ) iwhere cnt_ad_prec <> cnt_prec or      cnt_ad_foll <> cnt_foll or      addeddate is null;order by id;

This returns all rows that have NULL in the column or are within three rows of a NULL.

The need for the comparison to the count is to avoid the edge issues on the smallest and largest ids.

Another way:

SELECT i1.*    FROM Items i1, Items i2        WHERE i2.AddedDate IS NULL AND ABS(i1.ID - i2.ID) <= 3

I hope there is index on AddedDate column.