use case when to control the order index : Case Query « Select Query « Oracle PL / SQL






  1. Oracle PL / SQL
  2. Select Query
  3. Case Query

use case when to control the order index

   
SQL>
SQL>
SQL> create table emp
  2  ( empno      NUMBER(4)    constraint E_PK primary key
  3  , ename      VARCHAR2(8)
  4  , init       VARCHAR2(5)
  5  , job        VARCHAR2(8)
  6  , mgr        NUMBER(4)
  7  , bdate      DATE
  8  , sal        NUMBER(6,2)
  9  , comm       NUMBER(6,2)
 10  , deptno     NUMBER(2)    default 10
 11  ) ;

Table created.

SQL> insert into emp values(1,'Tom','N',   'TRAINER', 13,date '1965-12-17',  800 , NULL,  20);

1 row created.

SQL> insert into emp values(2,'Jack','JAM', 'Tester',6,date '1961-02-20',  1600, 300,   30);

1 row created.

SQL> insert into emp values(3,'Wil','TF' ,  'Tester',6,date '1962-02-22',  1250, 500,   30);

1 row created.

SQL> insert into emp values(4,'Jane','JM',  'Designer', 9,date '1967-04-02',  2975, NULL,  20);

1 row created.

SQL> insert into emp values(5,'Mary','P',  'Tester',6,date '1956-09-28',  1250, 1400,  30);

1 row created.

SQL> insert into emp values(6,'Black','R',   'Designer', 9,date '1963-11-01',  2850, NULL,  30);

1 row created.

SQL> insert into emp values(7,'Chris','AB',  'Designer', 9,date '1965-06-09',  2450, NULL,  10);

1 row created.

SQL> insert into emp values(8,'Smart','SCJ', 'TRAINER', 4,date '1959-11-26',  3000, NULL,  20);

1 row created.

SQL> insert into emp values(9,'Peter','CC',   'Designer',NULL,date '1952-11-17',  5000, NULL,  10);

1 row created.

SQL> insert into emp values(10,'Take','JJ', 'Tester',6,date '1968-09-28',  1500, 0,     30);

1 row created.

SQL> insert into emp values(11,'Ana','AA',  'TRAINER', 8,date '1966-12-30',  1100, NULL,  20);

1 row created.

SQL> insert into emp values(12,'Jane','R',   'Manager',   6,date '1969-12-03',  800 , NULL,  30);

1 row created.

SQL> insert into emp values(13,'Fake','MG',   'TRAINER', 4,date '1959-02-13',  3000, NULL,  20);

1 row created.

SQL> insert into emp values(14,'Mike','TJA','Manager',   7,date '1962-01-23',  1300, NULL,  10);

1 row created.

SQL> select job, ename
  2  ,      case
  3           when sal <= 2500
  4           then 'cheap'
  5           else 'expensive'
  6         end         as class
  7  from   emp
  8  where  bdate < date '1964-01-01'
  9  order  by case job
 10            when 'Designer' then 1
 11            when 'Designer'  then 2
 12                            else 3
 13            end;
Enter...

Designer Black    expensive
Designer Peter    expensive
Tester   Mary     cheap
Manager  Mike     cheap
TRAINER  Smart    expensive
TRAINER  Fake     expensive
Tester   Wil      cheap
Tester   Jack     cheap

8 rows selected.

SQL>
SQL> drop table emp;

Table dropped.

SQL>








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