Oracle PL/SQL Tutorial/Table Joins/natural join

Natural join two tables

   <source lang="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> SQL> create table history

 2  ( empno      NUMBER(4)
 3  , beginyear  NUMBER(4)
 4  , begindate  DATE
 5  , enddate    DATE
 6  , deptno     NUMBER(2)
 7  , msal       NUMBER(6,2)
 8  , comments   VARCHAR2(60)
 9  ) ;

Table created. SQL> SQL> SQL> SQL> insert into history values (9,2000,date "2000-01-01",date "2002-01-02",40, 950,"history for 9"); 1 row created. SQL> insert into history values (8,2000,date "2000-01-02", NULL ,20, 800,""); 1 row created. SQL> insert into history values (7,1988,date "2000-01-06",date "2002-01-07",30,1000,""); 1 row created. SQL> insert into history values (6,1989,date "2000-01-07",date "2002-01-12",30,1300,""); 1 row created. SQL> insert into history values (5,1993,date "2000-01-12",date "2002-01-10",30,1500,"history for 5"); 1 row created. SQL> insert into history values (4,1995,date "2000-01-10",date "2002-01-11",30,1700,""); 1 row created. SQL> insert into history values (3,1999,date "2000-01-11", NULL ,30,1600,""); 1 row created. SQL> insert into history values (2,1986,date "2000-01-10",date "2002-01-08",20,1000,"history for 2"); 1 row created. SQL> insert into history values (1,1987,date "2000-01-08",date "2002-01-01",30,1000,"history for 1"); 1 row created. SQL> insert into history values (7,1989,date "2000-01-01",date "2002-05-12",30,1150,"history for 7"); 1 row created. SQL> SQL> SQL> SQL> select ename, beginyear, msal, deptno

 2  from   employees
 3         natural join
 4         history;

no rows selected SQL> SQL> drop table history; Table dropped. SQL> SQL> drop table employees; Table dropped. SQL></source>