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SQL>
SQL> create table history
2 ( empno NUMBER(4)
3 , beginyear NUMBER(4)
4 , begindate DATE
5 , enddate DATE
6 , deptno NUMBER(2)
7 , sal NUMBER(6,2)
8 , comments VARCHAR2(60)
9 , constraint H_PK primary key (empno,begindate)
10 , constraint H_BEG_END check (begindate < enddate)
11 ) ;
Table created.
SQL>
SQL>
SQL> alter session set NLS_DATE_FORMAT='DD-MM-YYYY';
Session altered.
SQL>
SQL> insert into history values (1,2000,'01-01-2000','01-02-2000',40, 950,'');
1 row created.
SQL> insert into history values (1,2000,'01-02-2000', NULL ,20, 800,'restarted');
1 row created.
SQL> insert into history values (2,2009,'01-11-2009', NULL ,30,1600,'just hired');
1 row created.
SQL>
SQL>
SQL> select empno, begindate, sal
2 , LAG(sal) over
3 ( partition by empno
4 order by empno, begindate
5 ) as prev_sal
6 , LEAD(sal) over
7 ( partition by empno
8 order by empno, begindate
9 ) as next_sal
10 from history
11 order by empno, begindate;
EMPNO BEGINDATE SAL PREV_SAL NEXT_SAL
---------- ---------- ---------- ---------- ----------
1 01-01-2000 950 800
1 01-02-2000 800 950
2 01-11-2009 1600
SQL>
SQL> drop table history;
Table dropped.
SQL>
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