How find last number of sequence numbers in sql?

Question

I want find last number of sequence in sql query for fill automatically suggestion field value. forexample my code field(column) is :1,2,3,4,10,20 so i want found 4 in my query

Answer 1

If your table is called table_name and looks like this:

id
1
2
3
4
10
20

Then this should work:

select min(previd) from 
(select id, lag(id) over(order by id) as previd
from table_name) t
where id - previd > 1;

Fiddle