How to get the next number in a sequence

Question

I have a table like this:

+----+-----------+------+-------+--+
| id | Part      | Seq  | Model |  |
+----+-----------+------+-------+--+
| 1  | Head      | 0         


        

Answer 1

Since you want the sequence to be based on the a specific model, just add that into the where clause when doing the select. This will ensure the Max(SEQ) pertains only to that model series. Also since the SEQ can be null wrap it in a ISNULL, so if it is null it will be 0, so 0 + 1, will set the next to 1. The basic way to do this is :

Insert into yourtable(id, Part, Seq, Model)
    Select 6, 'Groin', ISNULL(max(Seq),0) + 1, 3 
    From yourtable
    where MODEL = 3;