Answers for "when to use is and as in oracle procedure"

syntax of procedure in oracle

CREATE OR REPLACE PROCEDURE procedure_name
    [ (parameter [,parameter]) ]

IS
    [declaration_section]

BEGIN
    executable_section

[EXCEPTION
    exception_section]

END [procedure_name];

EXECUTE procedure_name(?,?,?);

oracle procedure as vs is

FUNCTION sal_ok (salary REAL, title VARCHAR2) RETURN BOOLEAN IS
   min_sal REAL;
   max_sal REAL;
BEGIN
   SELECT losal, hisal INTO min_sal, max_sal FROM sals
      WHERE job = title;
   RETURN (salary >= min_sal) AND (salary <= max_sal);
END sal_ok;