create table employee (
   employee_id bigint not null primary key,
   first_name varchar(50) not null,
   middle_name varchar(50) null,
   last_name varchar(50) not null
)

create table eligibility (
   eligibility_id bigint not null primary key,
   employee_id bigint not null foreign key references employee (employee_id),
   effective_date date not null,
   sequence_number int not null,
   value varchar(20) not null,
   constraint UK_eligibility unique (employee_id, effective_date, sequence_number)
)

insert into employee (employee_id, first_name, middle_name, last_name) values (1001, 'A', 'B', 'C')

insert into eligibility (eligibility_id, employee_id, effective_date, sequence_number, value) values (1, 1001, '2016-04-13', 1, 'NS')
insert into eligibility (eligibility_id, employee_id, effective_date, sequence_number, value) values (2, 1001, '2016-05-25', 1, 'EX')
insert into eligibility (eligibility_id, employee_id, effective_date, sequence_number, value) values (3, 1001, '2016-05-25', 2, 'VR')
insert into eligibility (eligibility_id, employee_id, effective_date, sequence_number, value) values (4, 1001, '2016-06-05', 1, 'LS')

select * from eligibility e
where
    e.effective_date = (select max(effective_date)
                            from eligibility e1
                            where e1.employee_id = e.employee_id and
                                e1.effective_date <= '2016-05-30') AND
    e.sequence_number = (select max(sequence_number)
                            from eligibility e2
                            where e2.employee_id = e.employee_id and
                                e2.effective_date = e.effective_date)