-- There are three different syntax formats for these types of statements:
 
-- Syntax #1: IF-THEN
 
    IF condition THEN
             {...statements...}
    END IF;
 
 
-- Syntax #2: IF-THEN-ELSE
 
    IF condition THEN
             {...statements...}
    ELSE
             {...statements...}
    END IF;
 
 
-- Syntax #3: IF-THEN-ELSIF
 
    IF condition THEN
             {...statements...}
    ELSIF condition THEN
             {...statements...}
    ELSE
             {...statements...}
    END IF;
 
 
-- Sample IF Statement Function:
 
CREATE OR REPLACE FUNCTION fn_price(pProd VARCHAR2)
RETURN PLS_INTEGER IS
 tabPrice discounts.prodprice%TYPE;
 tabDisc  discounts.proddisc%TYPE;
 i        PLS_INTEGER; 
BEGIN
  SELECT COUNT(*)
  INTO i
  FROM discounts
  WHERE prodname = pProd;
 
  IF i <> 0 THEN
    SELECT prodprice, proddisc
    INTO tabPrice, tabDisc
    FROM discounts
    WHERE prodname = pProd;
 
    RETURN tabPrice - (tabPrice * tabDisc/100);
  ELSE
    RETURN 0;
  END IF; 
EXCEPTION
  WHEN OTHERS THEN
    RETURN 0;
END fn_price;
/