Use user-defined function in if statement : Function Definition « Stored Procedure Function « Oracle PL / SQL

1. Oracle PL / SQL
2. Stored Procedure Function
3. Function Definition

Use user-defined function in if statement

    
SQL>
SQL> set serveroutput on
SQL>
SQL>
SQL>
SQL> CREATE TABLE session (
  2    department       CHAR(3),
  3    course           NUMBER(3),
  4    description      VARCHAR2(2000),
  5    max_lecturer     NUMBER(3),
  6    current_lecturer NUMBER(3),
  7    num_credits      NUMBER(1),
  8    room_id          NUMBER(5)
  9    );

Table created.

SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
  2              VALUES ('HIS', 101, 'History 101', 30, 11, 4, 20000);

1 row created.

SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
  2              VALUES ('HIS', 301, 'History 301', 30, 0, 4, 20004);

1 row created.

SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
  2              VALUES ('CS', 101, 'Computer Science 101', 50, 0, 4, 20001);

1 row created.

SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
  2              VALUES ('ECN', 203, 'Economics 203', 15, 0, 3, 20002);

1 row created.

SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
  2              VALUES ('CS', 102, 'Computer Science 102', 35, 3, 4, 20003);

1 row created.

SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
  2              VALUES ('MUS', 410, 'Music 410', 5, 4, 3, 20005);

1 row created.

SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
  2              VALUES ('ECN', 101, 'Economics 101', 50, 0, 4, 20007);

1 row created.

SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
  2              VALUES ('NUT', 307, 'Nutrition 307', 20, 2, 4, 20008);

1 row created.

SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
  2              VALUES ('MUS', 100, 'Music 100', 100, 0, 3, NULL);

1 row created.

SQL>
SQL>
SQL> CREATE OR REPLACE FUNCTION AlmostFull (
  2    p_Department session.department%TYPE,
  3    p_Course     session.course%TYPE)
  4    RETURN BOOLEAN IS
  5
  6    studentCount NUMBER;
  7    studentMax     NUMBER;
  8    v_ReturnValue     BOOLEAN;
  9    v_FullPercent     CONSTANT NUMBER := 80;
 10  BEGIN
 11    SELECT current_lecturer, max_lecturer
 12      INTO studentCount, studentMax
 13      FROM session
 14      WHERE department = p_Department
 15      AND course = p_Course;
 16
 17    IF (studentCount / studentMax * 100) >= v_FullPercent THEN
 18      v_ReturnValue := TRUE;
 19    ELSE
 20      v_ReturnValue := FALSE;
 21    END IF;
 22
 23    RETURN v_ReturnValue;
 24  END AlmostFull;
 25  /

Function created.

SQL>
SQL>
SQL> DECLARE
  2    CURSOR c_session IS
  3      SELECT department, course
  4        FROM session;
  5  BEGIN
  6    FOR v_ClassRecord IN c_session LOOP
  7      IF AlmostFull(v_ClassRecord.department, v_ClassRecord.course) THEN
  8        DBMS_OUTPUT.PUT_LINE(v_ClassRecord.department || ' ' || v_ClassRecord.course || ' is almost full!');
  9      END IF;
 10    END LOOP;
 11  END;
 12  /
MUS 410 is almost full!

PL/SQL procedure successfully completed.

SQL>
SQL> drop table session;

Table dropped.

   
    
    
  

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