IF-THEN-ELSE Statement

IF-THEN

DECLARE
v_num1 NUMBER(10);
v_num2 NUMBER(10);

BEGIN
  v_num1 := 2;
  v_num2 := 1;

  IF v_num1 > v_num2 THEN
     dbms_output.put_line('v_num1 is bigger than v_num2');
  END IF;
END;

IF-THEN-ELSE

DECLARE
v_num1 NUMBER(10);
v_num2 NUMBER(10);

BEGIN
  v_num1 := 2;
  v_num2 := 10;

  IF v_num1 > v_num2 THEN
     dbms_output.put_line('v_num1 is bigger than v_num2');
  ELSE
    dbms_output.put_line('v_num1 is NOT bigger than v_num2');
  END IF;
END;

IF-THEN-ELSIF-ELSE

DECLARE
v_num1 NUMBER(10);
v_num2 NUMBER(10);

BEGIN
  v_num1 := 2;
  v_num2 := 2;

  IF v_num1 > v_num2 THEN
     dbms_output.put_line('v_num1 is bigger than v_num2');
  ELSIF v_num1 < v_num2 THEN
    dbms_output.put_line('v_num1 is NOT bigger than v_num2');
  ELSE
    dbms_output.put_line('v_num1 is EQUAL to v_num2');
  END IF;
END;

Syntax

IF [condition 1] THEN

[statements to execute when condition 1 is TRUE];

ELSIF [condition 2] THEN

[statements to execute when condition 2 is TRUE];

ELSE

[statements to execute when both condition 1 & condition 2 are FALSE];

END IF;