In 18th Lessons, it has been given an example to calculate the area of ​​a circle. The formula to calculate the area of ​​a circle is pr2, where p is a constant with a value of 3:14 and r is the radius of the circle. The formula for calculating the circumference of a circle is 2pr2. The following PL/SQL block to calculate area of ​​a circle :

DECLARE
phi CONSTANT NUMBER := 3.14;
r NUMBER;
hasil NUMBER;
pilih VARCHAR2(1);
pilihan VARCHAR2(8);
BEGIN
r := &input_r;
pilih := '&luas_atau_keliling';--input L atau K
IF pilih = 'L' THEN
hasil := phi * r * r;
pilihan := 'Luas Lingkaran';
ELSE
hasil := 2 * phi * r;
pilihan := 'Keliling Lingkaran';
END IF;
DBMS_OUTPUT.PUT_LINE (pilihan||' = '||hasil);
END;
/

Above PL/SQL block will ask for 2 input values​​. The first input to fill the circle radius (r) and the second input to determine the choice area or circumstance of circle that will count. If the option on the input is L then will be loaded PL/SQL block that will calculate the area of ​​a circle, if the option is K then PL/SQL block will calculate the circumference of a circle.