case when : CASE « PL SQL Statements « Oracle PL/SQL Tutorial






SQL>
SQL>
SQL> -- create demo table
SQL> create table Employee(
  2    ID                 VARCHAR2(4 BYTE)         NOT NULL primary key,
  3    First_Name         VARCHAR2(10 BYTE),
  4    Last_Name          VARCHAR2(10 BYTE),
  5    Start_Date         DATE,
  6    End_Date           DATE,
  7    Salary             Number(8,2),
  8    City               VARCHAR2(10 BYTE),
  9    Description        VARCHAR2(15 BYTE)
 10  )
 11  /

Table created.

SQL>
SQL> -- prepare data
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2               values ('01','Jason',    'Martin',  to_date('19960725','YYYYMMDD'), to_date('20060725','YYYYMMDD'), 1234.56, 'Toronto',  'Programmer')
  3  /

1 row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values('02','Alison',   'Mathews', to_date('19760321','YYYYMMDD'), to_date('19860221','YYYYMMDD'), 6661.78, 'Vancouver','Tester')
  3  /

1 row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values('03','James',    'Smith',   to_date('19781212','YYYYMMDD'), to_date('19900315','YYYYMMDD'), 6544.78, 'Vancouver','Tester')
  3  /

1 row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values('04','Celia',    'Rice',    to_date('19821024','YYYYMMDD'), to_date('19990421','YYYYMMDD'), 2344.78, 'Vancouver','Manager')
  3  /

1 row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values('05','Robert',   'Black',   to_date('19840115','YYYYMMDD'), to_date('19980808','YYYYMMDD'), 2334.78, 'Vancouver','Tester')
  3  /

1 row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary, City,        Description)
  2                values('06','Linda',    'Green',   to_date('19870730','YYYYMMDD'), to_date('19960104','YYYYMMDD'), 4322.78,'New York',  'Tester')
  3  /

1 row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary, City,        Description)
  2                values('07','David',    'Larry',   to_date('19901231','YYYYMMDD'), to_date('19980212','YYYYMMDD'), 7897.78,'New York',  'Manager')
  3  /

1 row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary, City,        Description)
  2                values('08','James',    'Cat',     to_date('19960917','YYYYMMDD'), to_date('20020415','YYYYMMDD'), 1232.78,'Vancouver', 'Tester')
  3  /

1 row created.

SQL>
SQL>
SQL>
SQL> -- display data in the table
SQL> select * from Employee
  2  /


ID   FIRST_NAME           LAST_NAME            START_DAT END_DATE      SALARY CITY       DESCRIPTION
---- -------------------- -------------------- --------- --------- ---------- ---------- ---------------
01   Jason                Martin               25-JUL-96 25-JUL-06    1234.56 Toronto    Programmer
02   Alison               Mathews              21-MAR-76 21-FEB-86    6661.78 Vancouver  Tester
03   James                Smith                12-DEC-78 15-MAR-90    6544.78 Vancouver  Tester
04   Celia                Rice                 24-OCT-82 21-APR-99    2344.78 Vancouver  Manager
05   Robert               Black                15-JAN-84 08-AUG-98    2334.78 Vancouver  Tester
06   Linda                Green                30-JUL-87 04-JAN-96    4322.78 New York   Tester
07   David                Larry                31-DEC-90 12-FEB-98    7897.78 New York   Manager
08   James                Cat                  17-SEP-96 15-APR-02    1232.78 Vancouver  Tester

8 rows selected.

SQL>
SQL>
SQL>
SQL> select first_name, description
  2  ,      case when description   = 'Tester'    then '  10%'
  3              when description   = 'Developer' then '  20%'
  4              when first_name = 'Jason'     then '  30%'
  5                                       else '   0%'
  6         end  as raise
  7  from   employee;


FIRST_NAME           DESCRIPTION     RAISE
-------------------- --------------- -----
Jason                Programmer        30%
Alison               Tester            10%
James                Tester            10%
Celia                Manager            0%
Robert               Tester            10%
Linda                Tester            10%
David                Manager            0%
James                Tester            10%

8 rows selected.

SQL>
SQL>
SQL> -- clean the table
SQL> drop table Employee
  2  /

Table dropped.








22.2.CASE
22.2.1.CASE statements
22.2.2.When creating selector CASE statements, you cannot have NULL in the list of possible values.
22.2.3.Use CASE statement
22.2.4.Named case block
22.2.5.case when
22.2.6.An example of comparison of two numbers using a searched CASE expression
22.2.7.Variable assignment with case statement
22.2.8.Use case statement in a dbms_output.put_line
22.2.9.Simple CASE statement with range
22.2.10.Case statement to call procedure
22.2.11.Return statement with case
22.2.12.Use case statement in procedure call to use the proper parameter value