IF condition may be either a Boolean expression or Boolean variable.
SQL> SQL> create or replace function f_isSunday_tx (in_dt DATE) 2 return VARCHAR2-- from w w w . j a v a2 s . c o m 3 is 4 v_out_tx VARCHAR2(10); 5 v_flag_b BOOLEAN; 6 begin 7 v_flag_b := to_char(in_dt,'d')=1; 8 if v_flag_b then 9 v_out_tx:='Y'; 10 DBMS_OUTPUT.put_line('IsSunday=Y'); 11 end if; 12 return v_out_tx; 13 end; 14 / Function created. SQL> SQL> begin 2 DBMS_OUTPUT.put_line(f_isSunday_tx(SYSDATE)); 3 end; 4 / PL/SQL procedure successfully completed. SQL>