User_id should be one greater than the last

Question

i want to insert a new row and make the user_id one greater than the last user_id. anyone any ideas

Answer 1

user8652681 wrote:
ive wrote the code and it updates the row i want once, is there anyway i can change this so it adds a message into REPORT for evey instance of where last_login is < '05-MAY-09'
insert into REPORT (message_id)
     select max(message_id) + 1 from REPORT
     where exists
          select
               null
          from
               users u
          where
               last_login < '05-MAY-09'
)For that sort of thing you'll want a sequence.
SQL> select max(empno) from emp;
MAX(EMPNO)
      7934
SQL> create sequence empno_seq start with 7935 nocache;
Sequence created.
SQL> create table emp2 as select * from emp;
Table created.
SQL> insert into emp2
  2  select empno_seq.nextval, ename, job, mgr, hiredate, sal*2, 0, deptno
  3  from emp;
14 rows created.
SQL> select * from emp2;
     EMPNO ENAME      JOB              MGR HIREDATE         SAL       COMM     DEPTNO
      7369 SMITH      CLERK           7902 17-DEC-80        800                    20
      7499 ALLEN      SALESMAN        7698 20-FEB-81       1600        300         30
      7521 WARD       SALESMAN        7698 22-FEB-81       1250        500         30
      7566 JONES      MANAGER         7839 02-APR-81       2975                    20
      7654 MARTIN     SALESMAN        7698 28-SEP-81       1250       1400         30
      7698 BLAKE      MANAGER         7839 01-MAY-81       2850                    30
      7782 CLARK      MANAGER         7839 09-JUN-81       2450                    10
      7788 SCOTT      ANALYST         7566 19-APR-87       3000                    20
      7839 KING       PRESIDENT            17-NOV-81       5000                    10
      7844 TURNER     SALESMAN        7698 08-SEP-81       1500          0         30
      7876 ADAMS      CLERK           7788 23-MAY-87       1100                    20
      7900 JAMES      CLERK           7698 03-DEC-81        950                    30
      7902 FORD       ANALYST         7566 03-DEC-81       3000                    20
      7934 MILLER     CLERK           7782 23-JAN-82       1300                    10
      7935 SMITH      CLERK           7902 17-DEC-80       1600          0         20
      7936 ALLEN      SALESMAN        7698 20-FEB-81       3200          0         30
      7937 WARD       SALESMAN        7698 22-FEB-81       2500          0         30
      7938 JONES      MANAGER         7839 02-APR-81       5950          0         20
      7939 MARTIN     SALESMAN        7698 28-SEP-81       2500          0         30
      7940 BLAKE      MANAGER         7839 01-MAY-81       5700          0         30
      7941 CLARK      MANAGER         7839 09-JUN-81       4900          0         10
      7942 SCOTT      ANALYST         7566 19-APR-87       6000          0         20
      7943 KING       PRESIDENT            17-NOV-81      10000          0         10
      7944 TURNER     SALESMAN        7698 08-SEP-81       3000          0         30
      7945 ADAMS      CLERK           7788 23-MAY-87       2200          0         20
      7946 JAMES      CLERK           7698 03-DEC-81       1900          0         30
      7947 FORD       ANALYST         7566 03-DEC-81       6000          0         20
      7948 MILLER     CLERK           7782 23-JAN-82       2600          0         10
28 rows selected.
SQL>