create table temp_sal (emp  varchar2(10), sal_month  number, salary  number);

insert into temp_sal values ('aa', 1, 1500);
insert into temp_sal values ('bb', 1, 2000);
insert into temp_sal values ('cc', 1, 3000);
insert into temp_sal values ('aa', 4, 2000);
insert into temp_sal values ('aa', 8, 3000);
insert into temp_sal values ('aa', 11, 4500);
insert into temp_sal values ('bb', 3, 2800);
insert into temp_sal values ('bb', 6, 3700);
insert into temp_sal values ('bb', 9, 4200);
insert into temp_sal values ('bb', 11, 5300);
insert into temp_sal values ('cc', 6, 5700);
insert into temp_sal values ('cc', 10, 6200);

begin
  dbms_application_info.set_client_info('6');
end;
/

PL/SQL procedure successfully completed.

select distinct emp
      ,first_value(salary) over (partition by emp order by sal_month desc) salary
from   temp_sal
where  sal_month <= sys_context('userenv','client_info');

EMP       |    SALARY
----------|----------
aa        |      2000
bb        |      3700
cc        |      5700


begin
  dbms_application_info.set_client_info('5');
end;
/

PL/SQL procedure successfully completed.

select distinct emp
      ,first_value(salary) over (partition by emp order by sal_month desc) salary
from   temp_sal
where  sal_month <= sys_context('userenv','client_info');

EMP       |    SALARY
----------|----------
aa        |      2000
bb        |      2800
cc        |      3000

SQL> select * From temp_sal where name = 'aa' order by mon;

NA        MON        SAL
-- ---------- ----------
aa          1       1500
aa          4       2000
aa          8       3000
aa         11       4500

             Not this!
 1 - 1500    1500
 2 - 1500    1666.67
 3 - 1500    1833.33
 4 - 2000    2000
 5 - 2000    etc.
 6 - 2000
 7 - 2000
 8 - 3000
 9 - 3000
10 - 3000
11 - 4500
12 - 4500

SQL> SELECT t.name, t.sal
  2  FROM temp_sal t
  3  WHERE t.mon = (SELECT MAX(t1.mon) FROM temp_sal t1
  4                 WHERE t1.name = t.name
  5                   AND t1.mon < '&month'
  6                )
  7  ORDER BY t.name;
Enter value for month: 6
old   5:                             AND t1.mon < '&month'
new   5:                             AND t1.mon < '6'

NA        SAL
-- ----------
aa       2000
bb       2800
cc       3000

SQL>

select distinct emp
      ,first_value(salary) over (partition by emp order by sal_month desc) salary
from   temp_sal
where  sal_month = :b1
and    emp       = :b2

SQL> create table faq
  2  ( text char(2000)
  3  )
  4  /

Table created.

SQL> insert into faq values ('1');

1 row created.

SQL> insert into faq values ('2');

1 row created.

SQL> insert into faq values ('3');

1 row created.

SQL> insert into faq values ('4');

1 row created.

SQL> insert into faq values ('5');

1 row created.

SQL> insert into faq values ('6');

1 row created.

SQL> insert into faq values ('7');

1 row created.

SQL> delete faq where trim(text) in ('2', '3', '4', '5', '6');

5 rows deleted.

SQL> 
SQL> insert into faq values ('8');

1 row created.

SQL> 
SQL> select rowid
  2  ,      text
  3  from   faq
  4  order  by rowid
  5  /

ROWID               TEXT
------------------  ------------------------------------------
AAADd9AAEAAAAD1AAA  1
AAADd9AAEAAAAD1AAD  8
AAADd9AAEAAAAD3AAA  7