Oracle SQL - Searched CASE Expression Example

Introduction

The following code shows an example of a searched CASE expression.

select ename, job 
,      case when job = 'TRAINER' then '   10%' 
            when job = 'MANAGER' then '   20%' 
            when ename = 'SMITH' then '   30%' 
                                 else '    0%' 
       end  as raise 
from   emp 
order  by raise desc, ename; 
  

SMITH gets only a 10% raise, despite the fourth line of the query.

This is because he is a trainer, which causes the second line to result in a match; therefore, the remaining WHEN expressions are not considered.

Demo

SQL>
SQL>-- from   w  w  w  .  j a va 2s . com
SQL> drop table emp;

Table dropped.

SQL> create table emp(
  2  empno      NUMBER(4)    primary key,
  3  ename      VARCHAR2(8)  not null   ,
  4  init       VARCHAR2(5)  not null   ,
  5  job        VARCHAR2(8)             ,
  6  mgr        NUMBER(4)               ,
  7  bdate      DATE         not null   ,
  8  msal       NUMBER(6,2)  not null   ,
  9  comm       NUMBER(6,2)             ,
 10  deptno     NUMBER(2)    default 10) ;
SQL>
SQL> insert into emp values(7001,'SMITH','N',  'TRAINER', 7902,date '1975-12-17',  1800 , NULL, 20);
SQL> insert into emp values(7002,'ALLEN','JAM','SALESREP',7006,date '1971-05-20',  1600, 300,   30);
SQL> insert into emp values(7003,'WARD', 'TF' ,'SALESREP',7006,date '1972-03-02',  1250, 500,   10);
SQL> insert into emp values(7004,'JACK', 'JM', 'MANAGER', 7009,date '1977-04-02',  2975, NULL,  20);
SQL> insert into emp values(7005,'BROWN','P',  'SALESREP',7006,date '1976-09-28',  1250, 1400,  30);
SQL> insert into emp values(7006,'BLAKE','R',  'MANAGER', 7009,date '1973-11-01',  2850, NULL,  10);
SQL> insert into emp values(7007,'CLARK','AB', 'MANAGER', 7009,date '1975-06-09',  2450, NULL,  10);
SQL> insert into emp values(7008,'SCOTT','DEF','TRAINER', 7004,date '1979-11-26',  3000, NULL,  20);
SQL> insert into emp values(7009,'KING', 'CC', 'DIRECTOR',NULL,date '1972-10-17',  5000, NULL,  10);
SQL> insert into emp values(7010,'BREAD','JJ', 'SALESREP',7006,date '1978-09-28',  1500, 0,     30);
SQL> insert into emp values(7011,'ADAMS','AA', 'TRAINER', 7008,date '1976-12-30',  1100, NULL,  20);
SQL> insert into emp values(7012,'JONES','R',  'ADMIN',   7006,date '1979-10-03',  8000, NULL,  30);
SQL> insert into emp values(7902,'FORD', 'MG', 'TRAINER', 7004,date '1979-02-13',  3000, NULL,  20);
SQL> insert into emp values(7934,'MARY', 'ABC','ADMIN',   7007,date '1972-01-23',  1300, NULL,  10);
SQL>
SQL>
SQL> select ename, job
  2  ,      case when job = 'TRAINER' then '   10%'
  3              when job = 'MANAGER' then '   20%'
  4              when ename = 'SMITH' then '   30%'
  5                                   else '    0%'
  6         end  as raise
  7  from   emp
  8  order  by raise desc, ename;

ENAME    | JOB      | RAISE
-------- | -------- | ------
BLAKE    | MANAGER  |    20%
CLARK    | MANAGER  |    20%
JACK     | MANAGER  |    20%
ADAMS    | TRAINER  |    10%
FORD     | TRAINER  |    10%
SCOTT    | TRAINER  |    10%
SMITH    | TRAINER  |    10%
ALLEN    | SALESREP |     0%
BREAD    | SALESREP |     0%
BROWN    | SALESREP |     0%
JONES    | ADMIN    |     0%

ENAME    | JOB      | RAISE
-------- | -------- | ------
KING     | DIRECTOR |     0%
MARY     | ADMIN    |     0%
WARD     | SALESREP |     0%

14 rows selected.

SQL>