Use 'and' to connect two boolean expressions : Boolean « PL SQL Data Types « Oracle PL/SQL Tutorial

1. Oracle PL/SQL Tutorial
2. PL SQL Data Types
3. Boolean

SQL>
SQL> SET ECHO ON
SQL> SET SERVEROUTPUT ON
SQL> DECLARE
  2    age   POSITIVE;
  3
  4    current_year  NATURAL;    --a year of 00 is valid.
  5    current_month POSITIVE;
  6    current_day   POSITIVE;
  7
  8    birth_year    NATURAL;    --a year of 00 is valid.
  9    birth_month   POSITIVE;
 10    birth_day     POSITIVE;
 11
 12  BEGIN
 13
 14    current_year := 2121;
 15    current_month := 12;
 16    current_day := 13;
 17
 18
 19    birth_year := 1224;
 20    birth_month := 12;
 21    birth_day := 12;
 22
 23    IF current_month > birth_month THEN
 24      age := current_year - birth_year;
 25    ELSIF (current_month = birth_month) and (current_day >= birth_day) THEN
 26      age := current_year - birth_year;
 27    ELSE
 28      age := current_year - birth_year - 1;
 29    END IF;
 30  END;
 31  /


SQL>