CASE WHEN statement with variable : Case « PL SQL « Oracle PL / SQL

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

CASE WHEN statement with variable

  
SQL>
SQL>
SQL> CREATE TABLE lecturer (
  2    id               NUMBER(5) PRIMARY KEY,
  3    first_name       VARCHAR2(20),
  4    last_name        VARCHAR2(20),
  5    major            VARCHAR2(30),
  6    current_credits  NUMBER(3)
  7    );

Table created.

SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
  2                VALUES (10001, 'Scott', 'Lawson','Computer Science', 11);

1 row created.

SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major, current_credits)
  2                VALUES (10002, 'Mar', 'Wells','History', 4);

1 row created.

SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
  2                VALUES (10003, 'Jone', 'Bliss','Computer Science', 8);

1 row created.

SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
  2                VALUES (10004, 'Man', 'Kyte','Economics', 8);

1 row created.

SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
  2                VALUES (10005, 'Pat', 'Poll','History', 4);

1 row created.

SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
  2                VALUES (10006, 'Tim', 'Viper','History', 4);

1 row created.

SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
  2                VALUES (10007, 'Barbara', 'Blues','Economics', 7);

1 row created.

SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
  2                VALUES (10008, 'David', 'Large','Music', 4);

1 row created.

SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
  2                VALUES (10009, 'Chris', 'Elegant','Nutrition', 8);

1 row created.

SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
  2                VALUES (10010, 'Rose', 'Bond','Music', 7);

1 row created.

SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
  2                VALUES (10011, 'Rita', 'Johnson','Nutrition', 8);

1 row created.

SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
  2                VALUES (10012, 'Sharon', 'Clear','Computer Science', 3);

1 row created.

SQL>
SQL> select * from lecturer;

      ID FIRST_NAME           LAST_NAME            MAJOR                          CURRENT_CREDITS
-------- -------------------- -------------------- ------------------------------ ---------------
######## Scott                Lawson               Computer Science                         11.00
######## Mar                  Wells                History                                   4.00
######## Jone                 Bliss                Computer Science                          8.00
######## Man                  Kyte                 Economics                                 8.00
######## Pat                  Poll                 History                                   4.00
######## Tim                  Viper                History                                   4.00
######## Barbara              Blues                Economics                                 7.00
######## David                Large                Music                                     4.00
######## Chris                Elegant              Nutrition                                 8.00
######## Rose                 Bond                 Music                                     7.00
######## Rita                 Johnson              Nutrition                                 8.00

      ID FIRST_NAME           LAST_NAME            MAJOR                          CURRENT_CREDITS
-------- -------------------- -------------------- ------------------------------ ---------------
######## Sharon               Clear                Computer Science                          3.00

12 rows selected.

SQL> DECLARE
  2    v_Major lecturer.major%TYPE;
  3    v_CourseName VARCHAR2(10);
  4  BEGIN
  5    SELECT major
  6      INTO v_Major
  7      FROM lecturer
  8      WHERE ID = 10011;
  9
 10    CASE v_Major
 11      WHEN 'Computer Science' THEN
 12        v_CourseName := 'CS  101';
 13      WHEN 'Economics' THEN
 14        v_CourseName :='ECN 203';
 15      WHEN 'History' THEN
 16        v_CourseName := 'HIS 101';
 17      WHEN 'Music' THEN
 18        v_CourseName := 'MUS 100';
 19      WHEN 'Nutrition' THEN
 20        v_CourseName := 'NUT 307';
 21      ELSE
 22        v_CourseName := 'Unknown';
 23    END CASE;
 24
 25    DBMS_OUTPUT.PUT_LINE(v_CourseName);
 26  END;
 27  /
NUT 307

PL/SQL procedure successfully completed.

SQL>
SQL> drop table lecturer;

Table dropped.

   
  

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