SQL>
SQL> create table vacation
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 vacation values (1,2000,'01-01-2000','01-02-2000',40, 950,'');
1 row created.
SQL> insert into vacation values (1,2000,'01-02-2000', NULL ,20, 800,'restarted');
1 row created.
SQL> insert into vacation values (2,1995,'01-10-1995','01-11-2009',30,1700,'');
1 row created.
SQL> insert into vacation values (2,2009,'01-11-2009', NULL ,30,1600,'just hired');
1 row created.
SQL> insert into vacation values (3,1986,'01-10-1986','01-08-1987',20,1000,'');
1 row created.
SQL> insert into vacation values (3,1987,'01-08-1987','01-01-1989',30,1000,'On training');
1 row created.
SQL>
SQL> select comments
2 from vacation
3 where regexp_instr(comments, '[^ ]+', 1, 9) > 0;
no rows selected
SQL>
SQL>
SQL> drop table vacation;
Table dropped.