Create an automatic numbered SQL statement in oracle

Code
-- Create sequence first creates a sequence (here SEQ_LASTYEARDISCASE is the sequential column name)
Create sequence my sequence name
Minvalue 1
Max value 999999999999999999999999999
Start with 1
Increment by 1
Cache 20;

-- Create trigger
Create or replace trigger my trigger name
Before insert on my table name
For each row
Begin
Select My sequence name. nextval into: new. Auto-numbered column name in my table from dual;
End;