Question

The reason I need this for is that I made a column on my table called display_order, for now it’s smallint and the numbers were pre-determined.

However, when I insert a new record with my software I don’t know how to get the highest number in that column and add 1, so I thought about the possibility of an auto-incremented column where if I change 8 to 9 it will change everything else accordingly.

Is this possible?

Answer 1

However, when I insert a new record with my software I don’t know how to get the highest number in that column and add 1,

Insert MyTable( display_order, .... )
Select (
        Select Max(display_order) + 1
        From MyTable As T1
        ), ...
From MyTable

However, I wouldn’t recommend this. If display_order is user settable, then I would simply assume relative values. Thus, it wouldn’t matter if a user added two values with a display_order = 0. If you really want to go the extra mile and provide the ability to resequence the display_order, you could do it like so:

Update MyTable
Set display_order = Z.NewSeq
From    (
        Select PKCol
            , Row_Number() Over ( Order By display_order ) As NewSeq
        From MyTable
        ) As Z
    Join MyTable As T
        On T.PKCol = Z.PKCol