Oracle 18c

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create table Table_A (columnA varchar2(100), columnB number)
create sequence testS 
  MINVALUE 68900000
  MAXVALUE 68999005
  START WITH 68900000
  INCREMENT BY 1;
insert into Table_A(columnA) values ('Body Number')
1 rows affected

insert into Table_A(columnA) values ('Body Number')
1 rows affected

insert into Table_A(columnA) values ('Body Number')
1 rows affected

select * from Table_A;


COLUMNA
COLUMNB


Body Number
null

Body Number
null

Body Number
null


update Table_A
set columnB = testS.nextval
where columnA = 'Body Number';
3 rows affected

select * from Table_A;


COLUMNA
COLUMNB


Body Number
68900000

Body Number
68900001

Body Number
68900002