SELECT Query to get the Values in Case insensitive Format

Question

Hi ,
This is hari,
I want to select the user name in a table ex: username="HARI" or username='Hari' or username="HaRi" like this
If i wrote the query like
select username from userdb where username="Hari";
it is displaying the records which only matches "Hari" only .
can anybody help me out on this query asap please....
the query should return all the results
which matches any of the following strings as inputs "HARI" or "HaRi" or "hAri" or the like.
Awaiting for Response,
Thanks & Regards
Hari

Answer 1

Another solution is setting NLS_SORT to CI - case insensitive (or whatever_your_language_is_CI) and NLS_COMP to ANSI:
SQL> with t as (
  2             select 'HARI' name from dual union all
  3             select 'Hari' name from dual union all
  4             select 'HaRi' name from dual
  5            )
  6  select  *
  7    from  t
  8    where name = 'hArI'
  9  /
no rows selected
SQL> alter session set nls_sort = binary_ci
  2  /
Session altered.
SQL> alter session set nls_comp=ansi
  2  /
Session altered.
SQL> with t as (
  2             select 'HARI' name from dual union all
  3             select 'Hari' name from dual union all
  4             select 'HaRi' name from dual
  5            )
  6  select  *
  7    from  t
  8    where name = 'hArI'
  9  /
NAME
HARI
Hari
HaRi
SQL> SY.