Query a view with subquery : Select View « View « Oracle PL/SQL Tutorial






SQL>
SQL>
SQL>
SQL> create table employees(
  2    empno      NUMBER(4)
  3  , ename      VARCHAR2(8)
  4  , init       VARCHAR2(5)
  5  , job        VARCHAR2(8)
  6  , mgr        NUMBER(4)
  7  , bdate      DATE
  8  , msal       NUMBER(6,2)
  9  , comm       NUMBER(6,2)
 10  , deptno     NUMBER(2) ) ;

Table created.

SQL>
SQL>
SQL> insert into employees values(1,'Jason',  'N',  'TRAINER', 2,   date '1965-12-18',  800 , NULL,  10);

1 row created.

SQL> insert into employees values(2,'Jerry',  'J',  'SALESREP',3,   date '1966-11-19',  1600, 300,   10);

1 row created.

SQL> insert into employees values(3,'Jord',   'T' , 'SALESREP',4,   date '1967-10-21',  1700, 500,   20);

1 row created.

SQL> insert into employees values(4,'Mary',   'J',  'MANAGER', 5,   date '1968-09-22',  1800, NULL,  20);

1 row created.

SQL> insert into employees values(5,'Joe',    'P',  'SALESREP',6,   date '1969-08-23',  1900, 1400,  30);

1 row created.

SQL> insert into employees values(6,'Black',  'R',  'MANAGER', 7,   date '1970-07-24',  2000, NULL,  30);

1 row created.

SQL> insert into employees values(7,'Red',    'A',  'MANAGER', 8,   date '1971-06-25',  2100, NULL,  40);

1 row created.

SQL> insert into employees values(8,'White',  'S',  'TRAINER', 9,   date '1972-05-26',  2200, NULL,  40);

1 row created.

SQL> insert into employees values(9,'Yellow', 'C',  'DIRECTOR',10,  date '1973-04-27',  2300, NULL,  20);

1 row created.

SQL> insert into employees values(10,'Pink',  'J',  'SALESREP',null,date '1974-03-28',  2400, 0,     30);

1 row created.

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

Table created.

SQL>
SQL>
SQL> insert into registrations values (1, 'SQL',date '1999-04-12',4   );

1 row created.

SQL> insert into registrations values (2, 'SQL',date '1999-12-13',NULL);

1 row created.

SQL> insert into registrations values (3, 'SQL',date '1999-12-13',NULL);

1 row created.

SQL> insert into registrations values (4, 'OAU',date '1999-08-10',4   );

1 row created.

SQL> insert into registrations values (5, 'OAU',date '2000-09-27',5   );

1 row created.

SQL> insert into registrations values (6, 'JAV',date '1999-12-13',2   );

1 row created.

SQL> insert into registrations values (7, 'JAV',date '2000-02-01',4   );

1 row created.

SQL> insert into registrations values (8, 'JAV',date '2000-02-01',5   );

1 row created.

SQL> insert into registrations values (9, 'XML',date '2000-02-03',4   );

1 row created.

SQL> insert into registrations values (10,'XML',date '2000-02-03',5   );

1 row created.

SQL> insert into registrations values (1, 'PLS',date '2000-09-11',NULL);

1 row created.

SQL> insert into registrations values (2, 'PLS',date '2000-09-11',NULL);

1 row created.

SQL> insert into registrations values (3, 'PLS',date '2000-09-11',NULL);

1 row created.

SQL>
SQL>
SQL> create table courses
  2  ( code        VARCHAR2(6)
  3  , description VARCHAR2(30)
  4  , category    CHAR(3)
  5  , duration    NUMBER(2)) ;

Table created.

SQL>
SQL>
SQL> insert into courses values('SQL','SQL course',    'GEN',4);

1 row created.

SQL> insert into courses values('OAU','Oracle course', 'GEN',1);

1 row created.

SQL> insert into courses values('JAV','Java course',   'BLD',4);

1 row created.

SQL> insert into courses values('PLS','PL/SQL course', 'BLD',1);

1 row created.

SQL> insert into courses values('XML','XML course',    'BLD',2);

1 row created.

SQL> insert into courses values('ERM','ERM course',    'DSG',3);

1 row created.

SQL> insert into courses values('PMT','UML course',    'DSG',1);

1 row created.

SQL> insert into courses values('RSD','C# course',     'DSG',2);

1 row created.

SQL> insert into courses values('PRO','C++ course',    'DSG',5);

1 row created.

SQL> insert into courses values('GEN','GWT course',    'DSG',4);

1 row created.

SQL>
SQL>
SQL>
SQL> create or replace view course_days as
  2  select   e.empno
  3  ,        e.ename
  4  ,        sum(c.duration) as days
  5  from     registrations  r
  6           join courses   c on (c.code  = r.course)
  7           join employees e on (e.empno = r.attendee)
  8  group by e.empno
  9  ,        e.ename;

View created.

SQL> select *
  2  from   course_days
  3  where  days > (select avg(days)
  4                  from   course_days);

 EMPNO      last_name         DAYS
------ -------------------- ------
     7 Red                       4
     2 Jerry                     5
     6 Black                     4
     1 Jason                     5
     3 Jord                      5
     8 White                     4

6 rows selected.

SQL>
SQL> drop table registrations;

Table dropped.

SQL>
SQL> drop table courses;

Table dropped.

SQL>
SQL> drop table employees;

Table dropped.

SQL>
SQL>








8.4.Select View
8.4.1.Performing a SELECT on a View
8.4.2.Perform select on columns in a view
8.4.3.Query a view with subquery