where comm = comm, compare with itself : Where « Query Select « Oracle PL/SQL Tutorial






  1. Oracle PL/SQL Tutorial
  2. Query Select
  3. Where
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> select ename, init
  2  from   employees
  3  where  comm = comm;

ENAME    INIT
-------- -----
Jerry    J
Jord     T
Joe      P
Pink     J

SQL>
SQL> drop table employees;

Table dropped.

SQL>
SQL>








2.3.Where
2.3.1.Filtering Rows Using the WHERE Clause
2.3.2.A WHERE Clause Is Added to the Statement
2.3.3.Using the WHERE and GROUP BY Clauses Together
2.3.4.Convert char to number implicit in where clause
2.3.5.Compare Number type in where clause
2.3.6.where with complated boolean expressions
2.3.7.Where with sub query
2.3.8.where comm = comm, compare with itself
2.3.9.Where with count from subquery
2.3.10.Do calculation in where clause