How to find “holes” in a table

Question

I recently inherited a database on which one of the tables has the primary key composed of encoded values (Part1*1000 + Part2).
I normalized that column, but I cannot ch

Answer 1

The best way is building a temp table with all IDs

Than make a left join.

declare @maxId int
select @maxId = max(YOUR_COLUMN_ID) from YOUR_TABLE_HERE


declare @t table (id int)

declare @i int
set @i = 1

while @i <= @maxId
begin
    insert into @t values (@i)
    set @i = @i +1
end

select t.id
from @t t
left join YOUR_TABLE_HERE x on x.YOUR_COLUMN_ID = t.id
where x.YOUR_COLUMN_ID is null