not exists and subquery : EXISTS « Query Select « Oracle PL/SQL Tutorial

1. Oracle PL/SQL Tutorial
2. Query Select
3. EXISTS

SQL>
SQL> create table offerings
  2  ( course     VARCHAR2(6)
  3  , begindate  DATE
  4  , trainer    NUMBER(4)
  5  , location   VARCHAR2(8)
  6  ) ;

Table created.

SQL> insert into offerings values ('SQL',date '2009-04-12',13,'DALLAS' );

1 row created.

SQL> insert into offerings values ('OAU',date '2009-08-10',4,'CHICAGO');

1 row created.

SQL> insert into offerings values ('SQL',date '2009-10-04',1,'SEATTLE');

1 row created.

SQL> insert into offerings values ('SQL',date '2009-12-13',1,'DALLAS' );

1 row created.

SQL> insert into offerings values ('JAV',date '2009-12-13',4,'SEATTLE');

1 row created.

SQL> insert into offerings values ('XML',date '2000-02-03',1,'DALLAS' );

1 row created.

SQL> insert into offerings values ('JAV',date '2000-02-01',11,'DALLAS' );

1 row created.

SQL> insert into offerings values ('PLS',date '2000-09-11',8,'DALLAS' );

1 row created.

SQL> insert into offerings values ('XML',date '2000-09-18',NULL,'SEATTLE');

1 row created.

SQL> insert into offerings values ('OAU',date '2000-09-27',13,'DALLAS' );

1 row created.

SQL> insert into offerings values ('ERM',date '2001-01-15',NULL, NULL    );

1 row created.

SQL> insert into offerings values ('PRO',date '2001-02-19',NULL,'DALLAS' );

1 row created.

SQL> insert into offerings values ('RSD',date '2001-02-24',8,'CHICAGO');

1 row created.

SQL> create table registrations
  2  ( attendee    NUMBER(4)
  3  , course      VARCHAR2(6)
  4  , begindate   DATE
  5  , evaluation  NUMBER(1)
  6  , constraint  R_PK        primary key(attendee,course,begindate)
  7  ) ;

Table created.

SQL>
SQL> insert into registrations values (2,'SQL',date '2009-04-12',4   );

1 row created.

SQL> insert into registrations values (14,'SQL',date '2009-04-12',5   );

1 row created.

SQL> insert into registrations values (6,'SQL',date '2009-04-12',4   );

1 row created.

SQL> insert into registrations values (11,'SQL',date '2009-04-12',2   );

1 row created.

SQL> insert into registrations values (8,'SQL',date '2009-10-04',NULL);

1 row created.

SQL> insert into registrations values (9,'SQL',date '2009-10-04',3   );

1 row created.

SQL> insert into registrations values (13,'SQL',date '2009-10-04',4   );

1 row created.

SQL> insert into registrations values (13,'SQL',date '2009-12-13',NULL);

1 row created.

SQL> insert into registrations values (6,'SQL',date '2009-12-13',NULL);

1 row created.

SQL> insert into registrations values (3,'OAU',date '2009-08-10',4   );

1 row created.

SQL>
SQL> select o.*
  2  from   offerings o
  3  where  not exists
  4        (select r.*
  5         from   registrations r
  6         where  r.course    = o.course
  7         and    r.begindate = o.begindate);

COURSE BEGINDATE     TRAINER LOCATION
------ ---------- ---------- --------
JAV    13-12-2009          4 SEATTLE
XML    03-02-2000          1 DALLAS
JAV    01-02-2000         11 DALLAS
PLS    11-09-2000          8 DALLAS
XML    18-09-2000            SEATTLE
OAU    27-09-2000         13 DALLAS
ERM    15-01-2001
PRO    19-02-2001            DALLAS
RSD    24-02-2001          8 CHICAGO

9 rows selected.

SQL> drop table offerings;

Table dropped.

SQL> drop table registrations;

Table dropped.

SQL>